Biomedical subjects
Publications and source records attributed to I Ikeda.
Basal cell carcinoma (BCC) originating from an epidermoid cyst which existed for about 50 years was seen in a 78-year-old Japanese male. Nests of basal cell carcinoma were connected with the epidermoid cyst, partially replacing the cyst wall.
We examined the expression of ret proto-oncogene (proto-ret) in surgically resected human neuroblastomas. Slot blot RNA hybridization revealed that all 29 neuroblastomas examined expressed the proto-ret, the relative intensity of the hybridization ranging from 1 to 48. No correlation was found between the level of expression of proto-ret and the clinical stage. The level of expression was also not correlated with N-myc amplification, the patient's age or the histological type of the tumor. Based on the previous finding that proto-ret expression is very rarely detected in tumor cell lines other than those of neuroblastoma, proto-ret expression was suggested to be a characteristic of neuroblastomas, and possibly to be involved in the genesis of neuroblastomas.
Platelet-activating factor (PAF) has been reported to play a role in the inflammatory reaction, but the mechanism of PAF in humans is still unclear. We examined the presence of PAF in pleural fluids from 23 patients with pleural effusion and in all cases detected PAF associated with eosinophil and/or neutrophil infiltrations. The amounts of PAF in pleural fluids were, respectively, 340, 50 to 170, and 1,250 to 2,130 fmol/ml for a patient with eosinophilic pneumonia, those with pneumothorax (n = 9), and empyema (n = 3). In contrast, patients with tuberculous pleuritis (n = 2), lung edema (n = 3), or malignant disease (n = 5) had no detectable amounts of pleural fluid PAF (less than or equal to 10 fmol/ml). The amount of PAF showed a close correlation with the numbers of eosinophils and neutrophils in the pleural fluids. Furthermore, PAF was mostly detected in the cellular fractions, and the molecular species of PAF from the patients with empyema were almost consistent with those of PAF generated by human blood neutrophils. These results indicate that neutrophils and, presumably, eosinophils were the cellular source of PAF in the pleural fluids in the pathologic state of inflammation.
Different aged male rats, 4 weeks or 9 months old, were fed diets containing either casein (CAS), milk whey protein (WHY) or soybean protein (SOY) with corn oil or sardine oil for 4 weeks. The hypocholesterolemic effect of SOY, compared to CAS, was more evident in rats fed corn oil than in those fed sardine oil, and in young rats than in adult rats, irrespective of dietary cholesterol. In contrast, the liver cholesterol-lowering effect of SOY was more marked in adult than in young rats in all experiments. WHY exerted an intermediate effect on the concentration of liver cholesterol. At both ages, the response of liver 3-hydroxy-3-methylglutaryl (HMG) CoA reductase activity was diverse and dependent upon the source of dietary fat and age of the animal. Fecal steroid excretion was significantly higher in rats fed SOY than in those fed either CAS or WHY, especially in adult rats. The results showed a diverse interaction of the protein type, fat and age in respect to lipid metabolism.
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The expression of the ret proto-oncogene (proto-ret), which possibly encodes two isoforms of a receptor-type tyrosine kinase, was examined in human tumor cell lines. Expression of the proto-ret mRNA was detected in all 11 neuroblastoma cell lines examined. The level of mRNA varied more than 100-fold in these neuroblastoma cell lines and was particularly high in three of them. On the other hand, 19 non-neuroblastoma tumor cell lines derived from solid tumors and a human diploid fibroblast cell line did not express any detectable levels of proto-ret mRNA. No remarkable amplification of the proto-ret or gross structural changes in the coding region were found in these neuroblastoma cell lines. The specific expression of the proto-ret in neuroblastomas suggests that the proto-ret product may have a role in cellular functions specific to neuroblastoma cells.
We have developed two-site immunoradiometric assay (IRMA) for quantitation of human serum IgE, using two different anti-IgE monoclonal antibodies which recognize different epitopes on IgE molecule. We obtained 25 different monoclonal antibodies classified seven groups, and then two different monoclonal antibodies were selected for bead coater and tracer after checking the titer and specificity of each antibody. IgE IRMA we developed here showed good performance in terms of specificity, sensitivity and reproducibility. No cross-reactivity to IgG, IgM and albumin in the level of normal range was observed. The sensitivity for IgE assay was 0.6 x 10(-3) IU/tube and measurable range was 0.01-20.0 IU/tube (0.5-10(3) IU/ml). Coefficient of variations of Intra assay were 2.2-4.3% and average recovery yield was 92.5-108%. Good correlations with Phadebas IgE PRIST and Pharmacia IgE RIA were obtained i.e., y = 1.12x-0.19 (r = 0.96) and y = 0.97x-5.9 (r = 9.7), respectively. These results indicate that the assay system will contribute much to the routine diagnosis for atopic allergy disease and parasitic infections.
Male Sprague-Dawley rats at the ages of four weeks and nine months were fed purified diets containing 20% proteins either as casein (CAS), milk whey protein (WHY), or soybean protein (SOY) with 5% sardine oil for four weeks. The hypocholesterolemic effect of SOY was not statistically evident as compared to milk proteins at both ages, although serum cholesterol tended to be low in the SOY groups. A significant age-dependent increase in serum cholesterol was observed in all dietary groups. Liver cholesterol concentrations were comparable in young rats, whereas in adults they were significantly lower in the SOY than in the CAS or WHY groups. At both ages, the activity of liver 3-hydroxy-3-methylglutaryl coenzyme A reductase tended to be higher in the SOY than in the other groups. Fecal steroid excretion was significantly higher in rats fed SOY than those fed either CAS or WHY, especially in adult rats. Significant age- and dietary protein-effects were observed in fatty acid profiles of liver microsomal phospholipids. Thus, the effects of dietary proteins on various lipid parameters were essentially maintained even when fish oil served as the source of dietary fat.
Male Sprague-Dawley rats four weeks or eight months of age were fed purified diets containing 10% fat, either as a blend of safflower oil and palm olein (polyunsaturated fatty acids, PUFA, 34%), a blend of linseed oil and palm olein (PUFA, 33%) or sardine oil (PUFA, 33%) for four weeks. In other trials, sterol contents were made equivalent by supplementing cholesterol to a blend of corn oil and palm olein (PUFA, 30%) or phytosterol to sardine oil (PUFA, 30%). Fish oil was hypolipidemic in rats of different ages, but it tended to increase liver cholesterol in adult animals and this was not improved by the addition of phytosterol. The age-dependent increase in liver cholesterol was not duplicated in rats fed a vegetable fat blend supplemented with cholesterol. At both ages, liver 3-hydroxy-3-methylglutaryl coenzyme A reductase activity was lower in the sardine oil than in the other groups. There were no significant age- or diet-related differences in the activity of liver cholesterol 7 alpha-hydroxylase. Fecal steroid excretion was comparable in age-matched rats fed diets supplemented either with cholesterol or phytosterol. Sardine oil reduced the delta 6-desaturase activity markedly as compared with linseed oil, and age-dependent reduction of the desaturase activity was observed in all dietary groups examined. Thus, the results showed a specific effect of fish oil on lipid metabolism.
We screened for immunoglobulin (Ig) production stimulating factor (IPSF) which enhanced Ig production of human-to-human hybridomas in serum-free culture, and found that culture supernatant and lysate of human lymphoblastoid Namalwa cells stimulated proliferation and Ig production of human-to-human hybridoma HB4C5 cells. The IPSF in Namalwa lysate was partially purified with DEAE-Toyopearl 650M, hydroxylapatite and Superose 6HR 10/30 column chromatographies. The partially purified IPSF was a macromolecule of about 500,000 dalton containing 72,000 dalton protein as a major component. The activity was stable at pH 6 to 12, but inactivated partially by heating over 40 degrees C (60% decrease) and completely by trypsin digestion. These results suggest that the IPSF activity is due to its protein and heat-stable components. The Namalwa IPSF stimulated proliferation of human-to-human hybridomas but not that of mouse-to-mouse hybridomas. The IPSF also stimulated Ig production of human-to-human hybridomas derived from NAT-30 cells, but not that of other human-to-human or mouse-to-mouse hybridomas. NAT-30 is a human fusion partner derived from Namalwa cells. These results suggest that the Namalwa IPSF is an autocrine factor that stimulates proliferation and Ig production of hybridomas derived from NAT-30 cells.
Okadaic acid is a non-phorbol 12-myristate 13-acetate (PMA)-type tumor promoter on mouse skin and known to be a potent inhibitor of serine/threonine protein phosphatases. Contrary to expectation from its tumor-promoting activity, okadaic acid was shown to have a potential to revert the phenotypes of cells transformed by raf and ret-II to that of normal cells. Two to 3 days after addition of 8 ng of okadaic acid per ml to the culture medium, raf and ret-II transformants changed to flat cells and gained contact inhibition. The amount of fibronectin, which was decreased in malignant transformed cells, was increased in the flat revertants. Moreover, okadaic acid caused a dose-dependent loss of ability to grow in soft agar. The morphology of the cells reverted to malignant phenotype within 1 week after removal of okadaic acid. The levels of mRNA and protein of activated c-raf in flat revertants were similar to those in parental transformed cells. The level of mRNA of ret-II was also not changed by flat reversion. No induction of flat reversion was observed with okadaic acid tetramethyl ether, an inactive compound, or a phorbol ester, PMA. As okadaic acid is a potent inhibitor of protein phosphatases 1 and 2A, the possibility that these phosphatases are involved in signal transduction from the raf and ret-II oncogenes is suggested.
1. Male rats at 1 (young) and 9 months (adult) of age were fed on purified diets, supplemented with or without cholesterol, containing 200 g protein/kg (casein (CAS), whey protein (WHY) or soya-bean protein (SOY] for 4 weeks. 2. SOY exerted a hypocholesterolaemic effect in young rats regardless of dietary cholesterol, whereas in adult rats it was observed only when a cholesterol-enriched diet was given. WHY was also hypocholesterolaemic in rats of both ages given cholesterol. SOY tended to reduce the liver cholesterol both in young and adult rats. 3. The liver hydroxymethylglutaryl-CoA reductase (NADPH) (EC 1.1.1.34) activity tended to be lower in the vegetable-protein groups than in the animal-protein groups in young rats, but the age-related reduction was observed only in the latter groups. 4. There was no significant age-related difference in the activity of liver cholesterol 7 alpha-monooxygenase (EC 1.14.13.17) in response to diets. However, when cholesterol was given, activity tended to decrease with age. Rats given SOY excreted more faecal steroids than those given casein, particularly adult rats. 5. The fatty acid profile of phosphatidylcholine and the delta 6-desaturase activity of liver microsomes indicated the reduced desaturation of linoleate in the SOY and WHY groups compared with the CAS groups. 6. The results thus showed a complex interaction of protein type, cholesterol and age on cholesterol homeostasis.
Lymph cannulated rats were administered intragastrically a test emulsion containing 25 mg of [14C]cholesterol, 50 mg of either guar gum, cellulose or chitosan, and 200 mg of either safflower, high-oleic safflower or palm oil, and the absorption of labeled cholesterol and fatty acids was measured. The type of both dietary fiber (P less than 0.001) and fat (P less than 0.05) significantly influenced cholesterol absorption. A significant interaction of fiber and fat on cholesterol absorption (P less than 0.05) was also observed. Chitosan effectively lowered cholesterol absorption more than did guar gum or cellulose, and this effect was more significant when given with safflower or high-oleic safflower oil than with palm oil. When guar gum was the source of dietary fiber, dietary fats did not modify cholesterol absorption. Dietary fiber also significantly affected triglyceride absorption (P less than 0.05). Absorption tended to be low in the chitosan, high in the cellulose and intermediate in the guar gum group. Absorption of safflower and high-oleic safflower oils tended to be higher than that of palm oil when cellulose or guar gum was fed. Guar gum, as compared with the other fibers, altered the absorption pattern of both cholesterol and triglyceride. The results showed that the type of dietary fat significantly influenced the effect that dietary fiber exerted on lipid absorption.
Digestion and absorption of cocoa butter and palm kernel oil and their effect on cholesterol absorption were studied in adult male rats. Duodenal and thoracic duct catheters were inserted surgically into the anesthetized rats. After an overnight fast, animals were given a single duodenal dose of an aqueous emulsion containing [1,2-3H]cholesterol and one of the following: corn oil, cocoa butter or palm kernel oil. Digestion and absorption were estimated by recovering the total fatty acids in the thoracic duct lymph over a 24-h collection period (after subtraction of the baseline "endogenous fatty acids" in the lymph). Intestinal absorption of cholesterol into the thoracic duct lymph was reduced significantly (P less than 0.05) in the presence of cocoa butter, compared to absorption when palm kernel oil or corn oil was administered. Compared to the absorption of corn oil (arbitrarily defined as 100%), the absorption of palm kernel oil and cocoa butter was 82 and 63%, respectively. The present study suggests that palm kernel oil absorption was not significantly different from that of corn oil. The lower absorbability of cocoa butter and its inhibitory effect on cholesterol absorption may explain in part why cocoa butter is less hypercholesterolemic and atherogenic than other equally saturated fats.
The effects of various n-6/n-3 (0.45-9.31) and polyunsaturated/saturated (P/S; 0.25-6.08) ratios of dietary fatty acids on various lipid parameters were studied in rats using a combination of palm oil, safflower oil, soybean oil and perilla oil. When the n-6/n-3 ratio was changed while maintaining a constant P/S ratio (1.2), the concentration of serum cholesterol tended to increase linearly with the increasing n-6/n-3 ratio, whereas liver cholesterol tended to decrease. Serum triglyceride level increased linearly up to a n-6/n-3 ratio of approximately 5, whereas liver triglyceride was not influenced. When the n-6/n-3 ratio was kept relatively constant (5.6-6.4), serum and liver cholesterol levels decreased up to a P/S ratio of approximately 2, whereas serum triglyceride tended to be low below this value. The ratio of arachidonate to linoleate in tissue phosphatidylcholine (PC) was also influenced by the n-6/n-3 and P/S ratios; it increased up to a n-6/n-3 ratio of approximately 4, whereas it decreased up to a P/S ratio of approximately 2. The percentage of eicosapentaenoic and docosahexaenoic acid (n-3) in tissue phosphatidylcholine was positively related to dietary n-3 fatty acid levels. Prostacyclin (PGI2) production by thoracic aorta reached a plateau at a n-6/n-3 ratio approximately 5, whereas it tended to decrease with an increasing P/S ratio. Platelet production of thromboxane A2 exhibited a parabola-like pattern with a peak value at a n-6/n-3 ratio of approximately 2, whereas it was independent of the P/S ratio.(ABSTRACT TRUNCATED AT 250 WORDS)
In a papillary thyroid carcinoma cell line, TPC-1, we found transcripts hybridizing to ret proto-oncogene (proto-ret) cDNA probes. The transcripts hybridized to the probes encoding the kinase domain but not to those of the transmembrane and extracellular domains of proto-ret. The sizes of the main transcripts in TPC-1 were aberrant, being 2.0, 2.5, 4.0 and 5.0 kb. In the neuroblastoma cell lines, the transcripts were 3.9, 4.5, 6.0 and 7.0 kb, which have been proved to be generated by alternative splicing and polyadenylation from the non-altered proto-ret oncogene. All of the four transcripts in TPC-1 are about 2 kb smaller than the corresponding ones in the neuroblastoma. From the length of the transcripts, it is suspected that the transcripts in TPC-1 are a rearranged form of proto-ret. This is the first report describing the aberrant transcripts of proto-ret in a human tumor.
The influence of sitosterol and sitostanol on the solubility of cholesterol in mixed bile salt micelles in vitro and in vivo was investigated to examine the mechanism by which sitostanol inhibits cholesterol absorption more than does sitosterol. Both sitosterol and sitostanol decreased micellar solubility of cholesterol to a similar extent, when determined with the turbidity. Also, these sterols reduced the concentration of cholesterol in micelles, both in vitro and in vivo. The extent of the reduction of micellar solubility of cholesterol by these sterols was almost the same in vitro, whereas sitostanol tended to reduce the solubility more effectively than sitosterol in vivo. Thus, the interference with cholesterol solubilization in vivo may be responsible for effective inhibition of cholesterol absorption by sitostanol. Since the effect of sitostanol was not observed in vitro, there is a possibility that another factor(s) not included in the in vitro system might affect the action of sitostanol on micellar solubility of cholesterol in vivo.