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Biomedical subjects

Y Seyama

Publications and source records attributed to Y Seyama.

At least 163 records · Page 9Linked to original sources
PubMed1986

A simultaneous quantitation of leukotriene B4 and its omega-oxidized products by gas chromatography-mass spectrometry.

We developed a highly sensitive and specific method for the simultaneous quantitation of leukotriene B4 (LTB4) and its omega-oxidized metabolites (20-hydroxy-LTB4 and 20-carboxy-LTB4) by mass fragmentography using deuterated compounds as internal standards. The ions produced by the cleavage of the C12-13 bond of the methyl ester dimethylisopropylsilyl ether derivatives of LTB4 and its metabolites were measured by selective ion monitorings. The detection limit of LTB4 was less than 10 pg and about 100-fold lower than that by high performance liquid chromatography. By using this method, the synthesis and further metabolism of LTB4 in human polymorphonuclear leukocytes were investigated.

Gas Chromatography-Mass Spectrometry↗
PubMed1986

Specific determination of arylsulfatase A activity.

Arylsulfatase activities in biological materials are too low to be detected by the methods available hitherto. A sensitive and specific assay method for arylsulfatase A (AS-A) has been developed in the present study. Ascorbate-2-sulfate is known to be a specific natural substrate of AS-A; the ascorbic acid liberated by the action of AS-A was quantitatively determined using HPLC equipped with an amperometric detector. The method was used to analyze the activity of AS-A in biological materials.

Animals↗
PubMed1986

Glucuronidated and sulfated bile acids in serum of patients with acute hepatitis.

The concentrations of glucuronidated and sulfated bile acids in the serum of 15 patients with acute hepatitis were determined by mass fragmentography. Total serum bile acid levels were 13.79-444.10 mumol/liter, and the percentages of glucuronidated and sulfated bile acids were in the wide ranges of 1.7-33% and 2.4-49%, respectively. In four of the five patients for whom serum bile acids were analyzed serially from the acute to the recovery stages of acute hepatitis, the decrease of the glucuronidated and sulfated bile acids was slower than that of nonglucuronidated, nonsulfated bile acids. Thus, the relative proportion of the glucuronides and sulfates in total bile acids apparently increased during the recovery phase. The mechanism for the relative predominance of bile acid esters in serum during recovery is unknown but might reflect an improved excretion of the nonesterified bile acids into bile after the rapid recovery of intrahepatic cholestasis.

Acute Disease↗
PubMed1986

Temperature- and growth-phase-dependent changes in membrane fatty acid compositions of Brevibacterium ammoniagenes.

Fatty acids newly synthesized by Brevibacterium ammoniagenes grown at different temperatures were analyzed. The assay temperature, not the growth temperature, was found to be the major factor affecting the unsaturated/saturated ratio of newly synthesized fatty acids in logarithmic-phase cells. However, in the stationary-phase cells the growth temperature also affected the product profile significantly; cells grown at 7 degrees C produced relatively more oleate and stearate and less palmitate and hexadecenoate when shifted up to 37 degrees C than did cells grown and assayed at 37 degrees C. The unsaturated/saturated ratio as well as average chain length of fatty acids also varied along with the progress of isothermal growth phase. These changes in fatty acid product profiles observed in vivo could be mimicked in vitro assays of the fatty acid synthetase by changing malonyl-CoA concentrations. Our results suggest that the malonyl-CoA concentration is a factor which, in addition to temperature, determines growth-phase-dependent and growth-temperature-dependent changes in the unsaturated/saturated ratios of fatty acids.

Acetates↗
PubMed1986

Characterization of leukotriene A4 synthase from murine mast cells: evidence for its identity to arachidonate 5-lipoxygenase.

Leukotriene A4 synthase was purified from the cytosolic fraction of murine mast cells. The enzyme converted 5-hydroperoxy-6-trans-8,11,14-cis-icosatetraenoic acid (5-HPETE) to leukotriene A4. This unstable product was identified by demonstration of two epimers of 6-transleukotriene B4, methanol trapping, as well as further transformation to leukotriene B4 by leukotriene A4 hydrolase. Leukotriene A4 synthase stereospecifically eliminated the D-hydrogen at C-10 (pro-R) in the synthesis of leukotriene A4 when incubated with [10D-3H;3-(14)C]5-HPETE. The purified enzyme also exhibited 5-lipoxygenase activity toward arachidonic acid and 8-lipoxygenase activity towards 8,11,14-cisicosatrienoic acid. All of these activities required Ca2+ and ATP for their maximal velocities. The effects of heat treatment and of several lipoxygenase inhibitors on these enzyme activities as well as coelution in various chromatographic systems strongly suggest that lipoxygenase and leukotriene A4 synthase activities reside in the same enzyme molecule.

Animals↗
PubMed1986

Biochemical diagnosis of cerebrotendinous xanthomatosis using reversed phase thin layer chromatography.

We developed a simple quantitative procedure for cholestanol in serum involving reversed phase thin layer chromatography. This procedure was satisfactory with regard to the linearity of the calibration curve in the range of 100 ng to 1,000 ng, recovery and reproducibility. Only 100 microliter of serum was needed for determination of the cholestanol concentration. Prior to thin layer chromatography, cholesterol was converted to alpha- and beta-epoxides with m-chloroperbenzoic acid, which were clearly distinguishable from cholestanol on TLC. Detection of sterols was performed by spraying with phosphomolybdic acid solution. Quantification of cholestanol was carried out with a TLC scanning densitometer. When serum cholestanol in cerebrotendinous xanthomatosis (CTX) patients was quantified by TLC, GC-MS, and GC, the correlation among the three methods was found to be approximately 1:1:1. It was found that the present method was useful for the primary diagnostic screening of CTX because of its simplicity and because many samples could be analyzed at one time.

Achilles Tendon↗
PubMed1986

Stereochemistry of 2,3-alkanediols obtained from the Harderian gland of Mongolian gerbil (Meriones unguiculatus).

The stereochemistry of the alcohol moieties of 2,3-alkanediol diacyl esters obtained from the Harderian gland of the Mongolian gerbil was investigated. There were five major 2,3-alkanediols, C14-C22 (even carbon numbers), all having the erythro configuration as determined by GC-MS analysis of their isopropylidene derivatives in comparison with synthetic erythro- and threo-2,3-hexadecanediols. 13C-NMR spectroscopy of the synthetic materials showed distinct differences of chemical shift at the C-1, C-3, and C-4 carbons, from which the native 2,3-alkanediols were definitely determined to be in the erythro series. The absolute configurations of the C-2 and C-3 asymmetric centers were assigned as 2S and 3R, respectively, based on known 2S,3R-octanediol.

Animals↗
PubMed1986

[Comparison of experimental diabetes induced by streptozotocin and cyproheptadine].

It is generally accepted that Diabetes mellitus is caused by the endocrinological functional disturbance of the pancreas, decreasing available insulin for carbohydrate metabolisms. Diabetes mellitus is not necessarily related to hypoinsulinemia, and some senile subjects show diabetic symptoms although the insulin levels in their blood are within the normal range. Therefore, in order to examine the cause of Diabetes mellitus, the glucose tolerance test is usually given as a routine laboratory method to monitor the pancreatic endocrine functions. The pattern of decreasing glucose level in blood will tell us what is the cause of the disease. In testing the effects of anti-diabetic drugs, experimental diabetic conditions have been prepared by various methods, and recently streptozotocin (STZ) and cyproheptadine (CPH) have been successfully used to induce diabetic conditions of various degrees. In the present study, degree of disturbance of the pancreatic functions by STZ and CPH were compared, and in addition, disturbance of organs other than the pancreas was also examined biochemically. When a high dose of STZ was given, irreversible disfunction of glucose level normalizing and insulin secreting abilities was observed. Serum GOT, GPT, lysosomal enzyme activities and lysosomal enzyme activity in the liver and pancreas decreased in high dose STZ administered rats. Low dose STZ disturbed the pancreatic endocrine function less than that in high dose STZ, and the blood glucose level normalizing function was reversibly disturbed. Insulin secretion decreased, and normalized on discontinuation of low dose STZ administration. Low dose STZ also disturbed organs other than the pancreas as in high dose STZ.(ABSTRACT TRUNCATED AT 250 WORDS)

Amylases↗
PubMed1986

[Stimulation of pituitary-adrenocortical system by cepharanthine].

We observed that cepharanthine might exert its anti-allergic action by stimulating the secretion of corticosterone. The present experiments were carried out to investigate stimulation of the pituitary-adrenocortical system by cepharanthine. Administration of cepharanthine to rats produced increases in plasma and adrenal corticosterone levels. Administration of cepharanthine to propranolol pretreated rats also produced increases in plasma and adrenal corticosterone levels and plasma ACTH level. The elevation of corticosterone level induced by cepharanthine was considered to be the specific effect of cepharanthine. Cepharanthine did not increase plasma corticosterone level in rats in the state of dexamethasone suppression of the pituitary-adrenocortical system, in which the level was lowered. Administration of cepharanthine to Bordetella pertussis vaccine induced beta-adrenergic blocked rats also produced increases in plasma and adrenal corticosterone levels. The production and release of corticosterone from an adrenal cell suspension were not influenced by cepharanthine in vitro. These results suggest that cepharanthine stimulates the pituitary-adrenotropic function.

Adrenal Glands↗
PubMed1986

[Effects of iodine-enriched egg (IE-egg) on nasal allergy: basic and clinical investigations].

The effect of iodine-enriched egg (IE-egg) on nasal allergy was investigated using an experimental allergic model. In addition, the effect of IE-egg was investigated using patients with yearly nasal allergy. IE-egg could suppress the leakage of pontamine sky blue dye in the experimental allergic model. beta-Glucuronidase activity in the perfusate was suppressed with the ingestion of IE-egg. The symptoms of the patients with yearly nasal allergy were mitigated by the ingestion of IE-egg. beta-Glucuronidase activity in the pituita of nasal allergic patients tended to be decreased.

Alkaloids↗
PubMed1986

[Effects of cepharanthine on experimental nasal allergy].

The anti-allergic actions of cepharanthine were examined using experimental nasal allergy rats (rhinitis models). In the actively sensitized rhinitis models, leaks of pontamine sky blue (PSB) dye in the perfusate of the nasal cavity were suppressed by cepharanthine treatment. Leaks of PSB dye in the perfusate were also suppressed by ketotifen treatment. beta-Glucuronidase activity in the perfusate was lower in the cepharanthine group and in the ketotifen group. In the passively sensitized rhinitis models, leaks of PSB dye in the perfusate were suppressed by cepharanthine treatment. Leaks of PSB dye in the perfusate in the ketotifen group were also suppressed. However, beta-glucuronidase activity was not different among the three groups. Cepharanthine (0.025-25 mg/kg body weight) and ketotifen (0.1-10 mg/kg body weight) inhibited leaks of PSB into the perfusate in a dose-dependent manner. These results suggest that cepharanthine may be clinically effective for treating patients with nasal allergy, and its anti-allergic mechanism may be the same as that of ketotifen.

Alkaloids↗
PubMed1985

The quaternary structure and activity of newly purified fatty acid synthetase from the Harderian gland of guinea-pig.

Fatty acid synthetase was isolated from the Harderian gland of guinea-pig. The fatty acids synthesized by the purified enzyme were analyzed by mass fragmentography. The purified enzyme had an inherent capacity to utilize methylmalonyl-CoA and synthesize methyl-branched fatty acids. Physicochemical studies indicated that an active enzyme was a dimer, consisted of two subunits of Mr = 2.5 X 10(5). The negatively stained enzyme had an electron micrographic image of an ellipsoidal contour with a continuous middle cleft along the major axis. The major and minor axes were approximately equal to 220 and 150 A, respectively. In a dimer, the subunit had a rod-like structure about 220 A long and 50 A wide. The enzyme was inactivated and dissociated into subunits by incubation at 0 degree C. The inactivated enzyme was fully reactivated by raising the temperature of the solution. The relationship between the quaternary structure of the enzyme and the occurrence of enzymatic activity was studied by high-performance liquid chromatography. Neither active monomers nor inactive dimers were found in inactivation and reactivation processes. The initial velocity of reactivation was proportional to the enzyme concentration over a concentration range of 160-800 micrograms/ml, indicating that the rate-determining step in the reactivation reaction was unimolecular.

Amino Acids↗
PubMed1985

Cytotoxic factor production by Kupffer cells elicited with Lactobacillus casei and Corynebacterium parvum.

The ability of Kupffer cells, spleen macrophages, pulmonary macrophages, and peritoneal macrophages (PM) to produce cytotoxic factor (CTF) was investigated in vitro. The production of CTF by Kupffer cells elicited with Corynebacterium parvum (CP) or Lactobacillus casei YIT9018 (LC9018) was higher than that of spleen, pulmonary macrophages, or PM. In addition, oxygen radical (OR) production by Kupffer cells or PM was measured. The production of OR by Kupffer cells or PM was significantly augmented by i.v. or i.p. injection of LC9018 or CP. No significant correlation was observed between the increase in OR production by Kupffer cells or PM and CTF production by Kupffer cells or PM elicited with either organism. It was suggested that activated Kupffer cells may be one important source of CTF production in serum and that the CTF-producing macrophages may be different from the OR-producing macrophages.

Adjuvants, Immunologic↗
PubMed1985

Serum concentrations of glucuronidated and sulfated bile acids in children with cholestasis.

Serum concentrations of nonglucuronidated-nonsulfated, glucuronidated, and sulfated bile acids in 9 control children and 16 children with cholestasis were quantitated by mass fragmentography. Total bile acid levels in control children were 19.55 +/- 2.78 mumol/liter (mean +/- SEM), and glucuronidated and sulfated bile acids comprised 2.6 +/- 0.5 and 17 +/- 3.1%, respectively. In 9 patients with congenital biliary atrasia, total bile acid levels were 167.34 +/- 11.18 mumole/liter of which 2.1 +/- 0.3% were glucuronidated and 15 +/- 1.4% were sulfated. Lithocholic and 3 beta-hydroxy-5-cholenoic acids, which have hepatotoxic effects, were presented in only small amounts in cholestatic children, and they were almost all glucuronidated or sulfated. The percentages of glucuronidated bile acids in control and cholestatic children were lower than in healthy and cholestatic adults, which may be explained by the lower activity of UDP-glucuronyltransferase in neonatal liver.

Adolescent↗
PubMed1985

Determination of 3 beta-hydroxy-5-cholenoic acid in serum of hepatobiliary diseases--its glucuronidated and sulfated conjugates.

3 beta-Hydroxy-5-cholenoic acid in the serum of control subjects and 62 patients with various hepatobiliary diseases was quantitated by mass fragmentography after separation into nonglucuronidated-nonsulfated, glucuronidated, and sulfated fractions. Deuterium-labeled deoxycholic acid and its glucuronide and sulfate were used as internal standards. Mean concentrations of total 3 beta-hydroxy-5-cholenoic acid in serum (mumole/liter) were as follows: Control subjects (14), 0.184; obstructive jaundice (15), 6.783; liver cirrhosis, compensated (12), 0.433, and decompensated (12), 1.636; chronic hepatitis (12), 0.241; and acute hepatitis (11), 2.364. Most of the 3 beta-hydroxy-5-cholenoic acid was glucuronidated or sulfated. Only in patients with obstructive jaundice did glucuronidation (60 +/- 14%) exceed sulfation (31 +/- 14%), sulfation exceeding glucuronidation in the others. The UDP-glucuronyltransferase might have different substrate specificities for 3 beta-hydroxy-5-cholenoic acid and other common bile acids, especially in the cholestatic state.

Adult↗
PubMed1985

Bile acid profiles in analbuminemia rats.

Bile acid profiles in serum, urine and bile of Nagase analbuminemia rats (NAR) and Sprague-Dawley rats (SDR) were examined. Serum bile acid levels in NAR (2.02 + 0.51 micrograms/ml, n = 15, M +/- S.E.) were markedly decreased as compared with those in SDR (20.86 +/- 3.72 micrograms/ml, n = 10). The unbound fraction of acids in serum examined by equilibrium dialysis was about ten times higher in NAR than in SDR. In the profiles of urinary and biliary bile acids in NAR and SDR, as big differences as seen for serum bile acids were not observed. Low bile acid levels in serum of NAR may reflect low bile acid binding capacity of NAR serum because the absence of albumin was thought to be one of the major causes of low bile acid levels in serum of NAR.

Aging↗
PubMed1985

Assay of fatty acid synthetase by mass fragmentography using [13C]malonyl-CoA.

A new assay method for fatty acid synthetase using mass fragmentography was described. [2-13C]Malonyl-CoA was chemically synthesized from [2-13C]malonic acid and used as a substrate. The newly synthesized fatty acids were quantitated with a GC-MS instrument after methyl esterification. Monitoring of molecular ions of the newly synthesized fatty acids enabled us to determine the absolute amounts with heptadecanoic acid as an internal standard. Multiple products (14 : 0, 16 : 0, and 18 : 0) were measured individually. Using this technique, we obtained information about production profiles such as that of chain length against incubation temperature and about malonyl-CoA decarboxylation activity in enzyme preparations, and we also confirmed the presence of malonyl-CoA decarboxylation activity even in purified fatty acid synthetase from guinea pig Harderian gland. Compared with the conventional assay methods (spectrophotometric and radioisotopic), this method was more reliable and useful.

Acetyl Coenzyme A↗