Fish oil diet affects on oxidative senescence of red blood cells linked to degeneration of spleen cells in mice.

The effect of dietary polyunsaturated fatty acids and alpha-tocopherol supplementation on erythrocyte lipid peroxidation and immunocompetent cells in mice was studied comparatively using seven dietary oils (15% oil/diet, w/w) including fish oil rich in eicosapentaenoic acid (EPA, 20:5, n-3) and docosahexaenoic acid (DHA, 22:6, n-3). A 43% increase in spleen weight, about twice as many spleen cells and no change in the subpopulations of spleen cells, as well as a significant depression of mitogen-induced blastogenesis of both T and B cells in the spleen were observed in mice fed fish oil for 30 days in comparison with soybean oil diet-fed mice. In the fish oil diet-fed mice, membranous lipid hydroperoxide (hydroperoxides of phosphatidylcholine and phosphatidylethanolamine) accumulation as a marker of oxidative senescence in red blood cells (RBC) was 2.7-3.5 times higher than that in mice fed soybean oil, although there was no difference in the plasma phosphatidylcholine hydroperoxide concentration. In spite of the supplementation of alpha-tocopherol to up to 10 times the level in the basal diet, the degeneration of spleen cells and the stimulated oxidative senescence of RBC found by the fish oil feeding could not be prevented. The results suggest that oral intake of excess polyunsaturated fatty acids, i.e. EPA and DHA, in a fish oil diet can lead to acceleration of membrane lipid peroxidation resulting in RBC senescence linked to the lowering of immune response of spleen cells, and that supplementation of alpha-tocopherol as antioxidant does not always effectively prevent such oxidative degeneration as observed in spleen cells and RBC in vivo.

[Sequential chemotherapy with methotrexate and 5-fluorouracil for advanced gastric cancer].

Sequential chemotherapy with methotrexate and 5-fluorouracil (MTX/5-FU) for advanced gastric cancer was given 29 patients. The procedure consisted of weekly MTX 100 mg/m2 (i.v.) followed three hours later by 5-FU 600 mg/m2 (i.v.) with leucovorin rescue on each of the following two days. Nine of 28 patients (32.1%) showed partial response to this treatment. Response rates were 28.6% in the 21 cases with poorly differentiated adenocarcinoma and 42.9% in the 7 cases with well- or moderately-differentiated adenocarcinoma. This procedure was especially effective for primary lesions (PR 9/20: 45%) and lymphnode metastases (CR 4 + PR 4, 8/17: 47.1%). Side effects were mild leukopenia and G-I symptoms such as nausea, diarrhea and loss of appetite, except in 1 patient who died of severe myelosuppression with sepsis. We concluded that sequential MTX/5-FU therapy is fairly effective and the adjuvant chemotherapy of choice for advanced or recurrent gastric cancer with not only poorly differentiated adenocarcinoma but also well- or moderately-differentiated adenocarcinoma.

Inhibitory effects of beta-carotene, palm carotene, and green tea polyphenols on pancreatic carcinogenesis initiated by N-nitorsobis(2-oxopropyl)amine in Syrian golden hamsters.

The effects of alpha-carotene, beta-carotene, palm carotene, and green tea polyphenols (GTP) on the progression stage of pancreatic carcinogenesis after rapid production of ductal lesions were studied in Syrian hamsters. Dose threshold inhibitory effects were noted for beta-carotene, 25 ppm, and palm carotene, 40 ppm, which includes 24 ppm beta-carotene reducing the numbers of putative preneoplastic lesions of duct epithelial hyperplasia and atypical hyperplasia, as well as carcinoma in situ and invasive carcinomas. GTP at doses of 500 and 5000 ppm, but not 100 ppm, also significantly decreased the numbers of hyperplasia and total duct lesions. Combined administration of 40 ppm palm carotene, and 50 ppm GTP similarly inhibited the lesion development. Alpha-carotene, however, did not affect pancreatic carcinogenesis. The results suggest that chemopreventive effects are exerted by beta-carotene and GTP above critical doses and that combined administration of palm carotene and GTP might be a candidate chemoprevention strategy for pancreatic cancer in humans.

Increased telomerase activity in hyperplastic nodules and hepatocellular carcinomas induced by a choline-deficient L-amino acid-defined diet in rats.

Activation of telomerase has been reported in several human cancers, including hepatocellular carcinomas (HCCs). We investigated telomerase activity during hepatocarcinogenesis induced by a choline-deficient L-amino acid-defined (CDAA) diet in rats. Male F344 rats were given a CDAA diet or a choline-supplemented L-amino acid-defined (CSAA) diet from 6 weeks of age for 75 weeks, and subgroups were killed 10 weeks, 50 weeks and 75 weeks after the beginning of the experiment. Hyperplastic nodules and HCCs were noted in rats fed a CDAA diet for 50 weeks and 75 weeks, respectively. Normal control liver specimens were obtained from 6-week-old rats. Telomerase activity was assessed by using a telomeric repeat amplification protocol (TRAP). Normal liver and background parenchyma of rats fed either of the diets for 10 weeks or 50 weeks showed weak telomerase activity. In contrast, markedly increased levels were demonstrated in hyperplastic nodules and HCCs. These results suggest that increased telomerase activity may be a biological feature of preneoplastic lesions that evolve to HCCs in rat liver.

Infrequent Ki-ras and an absence of p53 mutations in hepatocellular carcinomas induced by a choline deficient L-amino acid defined diet in rats.

Mutations of Ki-ras and p53 genes in hepatocellular carcinomas (HCCs) induced by the choline deficient L-amino acid defined (CDAA) diet in rats were investigated by polymerase chain reaction (PCR), single strand conformation polymorphism (SSCP) analysis followed by direct sequencing. Male Fischer 344 rats, 6 weeks old, were continuously given a CDAA diet for 70 weeks and then sacrificed. Macroscopically detectable nodules which were histologically confirmed to be well-differentiated HCCs were dissected free from the surrounding tissue and subjected to gene mutation analysis along with samples of non-tumor areas. Conformational change in the Ki-ras gene was detected in 1 out of 7 HCCs, involving a GGC to GTC transversion at codon 13. No p53 mutations were detected in 7 HCCs and also neither Ki-ras nor p53 mutations were found in non-tumor areas. The results suggest that neither Ki-ras nor p53 genes play an important role in hepatocarcinogenesis caused by long term expose to a CDAA diet in rats.

Function and modulation of the cloned glycine receptor channels expressed in Xenopus oocytes.

Complementary DNAs encoding glycine receptor subunits alpha 1 and alpha 2 were isolated from rat cDNA libraries. The alpha 2 protein had 71% homology to the alpha 1 protein. The alpha 1 mRNA is abundant in the spinal cord and brain stem of mature rats whereas the alpha 2 mRNA was expressed in the tissues during the restricted period from late embryonic (E18) to early postnatal stage (P10). Homomeric glycine receptor channels consisting of alpha 1 or alpha 2 subunit expressed in Xenopus oocytes had an ability to generate Cl- currents, and the currents were suppressed by strychnine, a selective antagonist. Single channel kinetics between the homomeric channels differed considerably (alpha 1 << alpha 2). The currents generated through homomeric alpha 1 receptor channels were augmented in the presence of Zn2+ (100 nM to 10 microM), and depressed by 4 beta-phorbol 12-myristate 13-acetate (10 nM), an activator of protein kinase C.

Antitumor effect of a Coliolus preparation, PSK: induction of macrophage chemotactic factor (MCF) in spleens of tumor bearing mice.

The effect of administration of PSK (Polysaccharide Kureha), a Coliolus preparation, in Meth-A solid tumors was analyzed in BALB/c mice. Spleen cells prepared from normal, non-treated Meth-A bearing, PSK-treated normal and PSK-treated tumor bearing mice were examined for induction of macrophage chemotatic factor (MCF). Only spleen cells from the latter mice produced MCF after 48 hrs of cultivation in the presence of Meth-A cells or concanavalin A (Con A). MCF-producing cells were indicated to be Lyt-1 positive, L3T4 positive and Lyt-2 negative cells in the negative elimination assay. There were no differences in the production of other cytokines including interleukin-2, interferon and tumor necrosing factor, spleen cells obtained other different groups of mice. The antitumor effect of either crude or purified MCF (molecular weight 100,000) was examined by daily consecutive intratumoral injections into Meth-A tumor tissues, and a significant inhibitory effect was detected.

The effect of dietary autoxidized oils on immunocompetent cells in mice.

Effects of dietary autoxidized oil on immunocompetent cells, such as splenocytes and thymocytes, were studied in mice. When the autoxidized methyl linoleate was administered orally to male C57BL/6 mice in a single dose, the DNA synthesis of thymocytes was remarkably depressed 1 day after the treatment, and then the mitogenic response to concanavalin A of splenocytes was increased 3 days after the dose. With long-term (90 days) feeding of slightly autoxidized soybean oil (with a peroxide value of 150 mequiv/kg) in mice, the DNA synthesis of thymocytes was depressed and the mitogenic response to concanavalin A of splenocytes was increased. No effect was observed on plasma glutamic acid-oxaloacetic acid transaminase and glutamic acid-pyruvic acid transaminase levels, nor on liver thiobarbituric acid reactants due to the dose of autoxidized soybean oil. These findings indicate that oral intake of autoxidized oil affects immunocompetent cells and causes depression of the DNA synthesis of thymocytes in mice.

[Serum thyrotropin concentrations in patients with Sheehan's syndrome: reevaluation of the usefulness in the diagnosis].

Serum concentrations of thyroid-stimulating hormone (TSH) were determined, using a highly sensitive immunoradiometric assay (IRMA), in 10 patients with Sheehan's syndrome. Serum TSH levels in these patients were from 2.3 to 9.0 microU/ml, with the mean of 6.4 +/- 2.3(SD) microU/ml, and the data were similar to those measured by a conventional RIA method. The levels of serum TSH in these patients were normal or even higher than those of healthy women (1.8 +/- 1.3 microU/ml). After supplement therapy by cortisol, serum TSH levels decreased, but remained within the detectable range that was greater than 0.15 microU/ml. After supplement therapy by 1-thyroxine (T4), serum TSH levels moderately decreased in all patients, and excessive 1-T4 administration resulted in a fall of serum TSH levels to lower than the detectable limit. Thyroidal 123 I uptake was low in 3 out of 6 patients examined, which supports a recent hypothesis of reduced biological activity of the patient's TSH. While, the remaining 3 patients had normal thyroidal 123 I uptake, and administration of perchlorate had no effects on thyroidal radioactivity. Thus, it may be possible that in the former group of patients the TSH has a reduced biological activity, and in the latter group of patients, iodine trapping is intact but further synthesis and secretion of thyroid hormone from the gland are impaired. When the response of serum TSH to TRH was examined, the peak serum TSH levels increased in all patients. The peak TSH levels were 4.8 to 10.2 microU/ml with the mean of 7.5 microU/ml, but the data overlapped with those of normal subjects (peak level ranging 5.9 approximately 27.7 microU/ml).(ABSTRACT TRUNCATED AT 250 WORDS)