Evaluation of exposure level of N-methyl-beta-carboline-3-carboxamide (FG 7142), an anxiogenic agent in humans

beta-Carboline-3-carboxylic acid methylamide (FG 7142), an anxiogenic agent, has been detected in human urine. The urinary excretion level of FG 7142 in non-smokers was found to be 0.503 +/- 0.25 ng per day (mean +/- S.D., n=10), while that in smokers was found to be 2.418 +/- 0.384 ng per day (n=10). This suggests that humans are exposed to FG 7142 and that smokers are exposed to higher levels of FG 7142 than non-smokers. Considering the previous findings that FG 7142 is present in cigarette smoke, indoor and outdoor air and smoke condensate of tree leaves, humans may be exposed to FG 7142 via the airways and lungs, although we cannot exclude the possibility of exposure via foodstuffs. Results of animal experiments suggest that FG 7142 which enters the bloodstream is excreted into the urine via the kidneys within 24 h in an unchanged form. Therefore, monitoring the level of FG 7142 in urine may be useful for monitoring the exposure level of FG 7142.

Immunochemical crossreactivity between globulins from buckwheat and indigo seeds

Immunochemical relationships between salt-soluble proteins (albumins plus globulins) from buckwheat and indigo seeds were shown by immunoblot and immunodiffusion analyses using rabbit antisera raised against buckwheat globulins. These antigenic crossreactivities were roughly consistent with their polypeptide components judged by two-dimensional electrophoresis and SDS-PAGE analyses.

Age-related changes in the susceptibility to clofibric acid, a hypolipidemic agent, of male rat liver

Age-related changes in the susceptibility to clofibric acid were investigated in male F344 rats of 8, 52, and 117 weeks old. Hepatomegaly, decrease of serum total cholesterol and triglyceride, increase of the total cytochrome P-450 contents, induction of the activities of microsomal omega-hydroxylation and peroxisomal beta-oxidation, proliferation of smooth endoplasmic reticulum and peroxisomes were detected in 8- and 52-week-old rats. In 117-week-old rats clofibric acid treatment resulted in decrease of serum total cholesterol, elevation of the activities of microsomal and peroxisomal enzymes, and slight proliferation of peroxisomes. These results suggest that the susceptibility of the male F344 rat liver to clofibric acid decreases in 117-week-old rats, though the effect is still recognizable.

[Assessment of formulas of predicted creatinine clearance from serum creatinine]

Much effects have offered to make formulas of predicted creatinine clearance (Ccr) from serum creatinine, sex, age, body weight and height. In this study, we examined 13 kinds of predicted formulas of Ccr that have been previously published. And instead of an actual body weight, we have attempted to use 4 kinds of ideal body weight (two of them reported in Japan, the others in United States) or a lean body weight. A total of 13 subjects were studied (2 healthy males and 11 males with chronic renal disease) to determine Ccr with urine collection for one hour and simultaneous measurement of inulin clearance (Cin). A highly statistical correlation between determined Ccr and predicted Ccr was observed. From predicted formula with one hour urine collection, standard error of estimation (SEE) was smallest. According to determined Cin, the subjects examined was divided into two groups (group A; Cin > or = 50 ml/min, group B; Cin < 50 ml/min). In most formulas, B group had higher correlation than A group, and each regression line got nearer to the identical line (Y = X) and SEE became smaller. The subjects examined were divided into two groups by body mass index (BMI). One is an obese and the other is a nonobese. In an obese group, SEE became smaller when an ideal body weight or a lean body weight were used in formulas instead of actual body weight. We could conclude that the clearance time and ideal or lean body weight of the patients are most important factors to assess predicted Ccr.

N-Methyl-beta-carboline-3-carboxamide (FG 7142): An anxiogenic agent in cigarette smoke condensate and its mechanism of formation

beta-Carboline-3-carboxylic acid methylamide (FG 7142), an anxiogenic agent has been found in cigarette smoke condensate, but not in the cigarette itself. When a cigarette, except its filter portion, was immersed in 20 ml of potassium phosphate buffer, pH 7.4, then heated at 60 degrees C for 2 days with or without presence of methylamine, FG 7142 was detected only in the mixture containing methylamine. Furthermore, when the mixtures of beta-carboline derivatives and various amounts of methylamine hydrochloride were heated at 60 degrees C for 5 days, FG 7142 was formed only in the mixtures containing methylamine and 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-caroxylic acid (MTCA) or 1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (TCCA). FG 7142 was also produced in the mixture of glucose, l-tryptophan and methylamine when heated at 200 degrees C in a dry condition. These observations suggest that FG 7142 is formed through the smoking process and that methylamine in cigarette smoke may play an important role in the formation of FG 7142.

N-Methyl-beta-carboline-3-carboxamide (FG 7142), an anxiogenic agent in airborne particles and cigarette smoke-polluted indoor air

beta-Carboline-3-carboxylic acid methylamide (FG 7142), an anxiogenic agent, has been measured in airborne particles, automobile-exhaust particles, incinerator ash, smoke condensate of tree leaves and cigarette-smoke-polluted indoor air by high-performance liquid chromatography. This compound has been detected in indoor as well as outdoor air. The source of this compound in indoor air was determined as cigarette smoke, identified from smoking machine studies. This anxiogenic agent was detected in smoke condensate of tree leaves and incinerator ash from garbage burning plants, but not in diesel-exhaust particles. Considering the present results, together with the previous finding that cigarette smoke contains this compound, FG 7142 is likely to be formed through combustion of plants. Our data also suggest that this compound may be widely distributed in the environment.

Age-related changes in thyroid lesions and function in F344/DuCrj rats

Age-related thyroid changes, such as those in weight, histology, morphometry, and hormonal concentrations were evaluated in 460 male and 460 female F344 rats from 9 to 109 weeks of age. The absolute weight of the thyroid increased with age in both sexes, but the relative weight was unaffected by age. Ectopic thymus and ultimobranchial cyst were observed in rats of both sexes from 9 to 109 weeks of age. The incidence of both congenital anomalies decreased with age. The incidence of follicular cyst, which was first observed in rats at 20 weeks of age, increased at 109 weeks. Hyperdistention of the follicle with infiltration of macrophages in the lumen and deposition of brown pigments in the cytoplasm of epithelial cells were observed in a few rats at 59 weeks of age. These follicular lesions were found in 29% of the males and 7% of the females at 109 weeks. The first thyroid tumor was seen at 59 weeks of age. In 109-week-old rats, 5% of males had follicular tumors, and 18% of males and 10% of females had C-cell tumors. At 82 weeks of age, the follicular area and the area of the follicular lumen increased, and the height of follicular epithelial cells decreased. Serum T3, T4 and TSH concentrations decreased with age and were significantly reduced at 82 weeks. These results suggest that in F344 male rats the thyroid structural and functional changes occurred with age, and thyroid function decreased after 82 weeks of age.

A case of intracytoplasmic edema of follicular epithelial cells in rat thyroid

Hydropic change of follicular epithelial cells in the thyroid was observed in a female Fischer 344 rat. Microscopically follicular epithelial cells were characterized by edematous swelling with weakly eosinophilic and homogeneous cytoplasm. The cytoplasm was negative for periodic acid-Schiff reaction, and thyroxine- and thyroglobulin-immunohistochemical reactions. Electron-microscopically, a small amount of amorphous substance was noted in remarkably dilated rough-surfaced endoplasmic reticulum (r-ER), and slight regressive changes of cytoplasmic organella were also observed. These morphological changes may indicate that focal intracytoplasmic edema was occurred in r-ER, and that the change belonged to hydropic degeneration of the thyroid follicular cells in the thyroid.

Comparison of antinociception induced by supraspinally administered L-arginine and kyotorphin

1. Intracerebroventricular (i.c.v.) or intracisternal (i.cist.) administration of kyotorphin (KTP), an endogenous Met-enkephalin releaser, at 5 micrograms per mouse, and L-arginine (L-Arg), a possible KTP precursor, at 30 micrograms per mouse, elicited antinociception in mice to a similar extent, as assessed by the tail-flick test. 2. Intracisternal preadministration of anti-KTP serum abolished the effect of i.cist. KTP and i.c.v. or i.cist. L-Arg, but not of i.c.v. KTP. 3. The antinociceptive effects of i.cist. KTP and of i.c.v. or i.cist. L-Arg disappeared in reserpinized mice, whereas the effect of i.c.v. KTP was unaffected by treatment of mice with reserpine. 4. Intrathecal (i.t.) phentolamine markedly reduced the antinociception induced by i.cist. KTP and by i.c.v. or i.cist. L-Arg, but not by i.c.v. KTP. 5. Intrathecal methysergide attenuated the antinociceptive effects of i.cist. KTP, but not of i.c.v. KTP and i.c.v. or i.cist. L-Arg. 6. These results suggest that the antinociception produced by i.cist. KTP, but not by i.c.v. KTP, is mediated by the brainstem-spinal noradrenergic and 5-hydroxytryptaminergic systems, and that L-Arg given i.c.v. or i.cist. increases KTP formation in the lower brain, possibly the brainstem, resulting in antinociception mediated by the descending noradrenergic system. Therefore, the regional distribution of KTP receptors and KTP synthetase in the brain does not appear to be common.

Effect of topical administration of L-arginine on formalin-induced nociception in the mouse: a dual role of peripherally formed NO in pain modulation

1. We investigated the effects of intraplantar (i.pl.) administration of L-arginine and NG-nitro-L-arginine methyl ester (L-NAME) on formalin-induced behavioural nociception in the mouse. 2. L- but not D-arginine, at 0.1-1 microgram per paw, coadministered with i.pl. formalin, enhanced the second-but not the first-phase nociceptive responses, whereas it was without significant effects at 3 micrograms per paw, and conversely, produced antinociception at 10 micrograms per paw, resulting in a bell-shaped dose-response curve. 3. L-NAME at 0.1-1 microgram per paw, when administered i.pl., exhibited antinociceptive activity in the second phase in a dose-dependent manner, although its D-enantiomer produced no effect. 4. An antinociceptive dose (1 microgram per paw) of L-NAME (i.pl.) considerably reduced the increase in second-phase nociception elicited by low doses (1 microgram per paw) of i.pl. L-arginine. The second-phase nociception decrease induced by a large dose (10 micrograms per paw) of i.pl. L-arginine was markedly reversed by i.pl. L-NAME at 0.1 micrograms per paw, raising it to a level above that of the control (formalin only). 5. These results suggest that peripheral NO plays a dual role in nociceptive modulation, depending on the tissue level, inducing either nociceptive or antinociceptive responses.

Comparative study of goitrogenic actions of 3-substituted 1, 2, 4-triazoles in rats

Antithyroid actions of 3-amino-1, 2, 4-triazole (ATZ), 3-mercapto-1, 2, 4-triazole (MTZ) and 3-nitro-1, 2, 4-triazole (NTZ), which are substituents on the 3-position of 1, 2, 4-triazole (TZ), and those of the parental compound, were compared in rats. After administration of either ATZ, MTZ, or NTZ, the thyroids of rats were enlarged with decreasing of colloid content and a proliferation of the follicular epithelia. The serum concentration of 3, 5, 3'-triiodothyronine and thyroxine decreased, while that of thyroid-stimulating hormone increased. ATZ, MTZ, and NTZ inhibited thyroid peroxidase activity both in vivo and in vitro. These antithyroid actions were the most remarkable in case of MTZ and were the least in case of NTZ. TZ had no effect on the thyroid function in vivo and in vitro. The results of Lineweaver-Burk analysis on the effect to lactoperoxidase activity indicated that ATZ, MTZ, and NTZ showed competitive inhibition. These results suggest that both MTZ and NTZ have goitrogenic effects on the thyroid through antiperoxidase action, such as ATZ. Thus, the 3rd carbon position of TZ is thought to be important for induction of goiter in rats. A comparison of the relationship between substituent on the 3-position of TZ and antithyroid activity shows that a mercapto moiety has more potent antithyroid action than an amino and a nitro moiety. It is concluded that the differences in antithyroid activity of TZ derivatives depend on the potency of the substituents.

Concentration of live retrovirus with a regenerated cellulose hollow fiber, BMM

A concentrated live retrovirus is required for in vitro experiments. A cuprammonium-regenerated cellulose hollow fiber, termed BMM, originally developed for biohazardous viral removal, was used to concentrate two different retroviruses, an ecotropic murine leukemia virus (MuLV) and human immunodeficiency virus (HIV). The BMM was useful for concentrating live virus suspension 10- to 30-fold from 500-1000 ml of culture supernatant. The ecotropic MuLV concentrated by BMM was demonstrated to be viable and biologically intact by XC plaque-forming assay and reverse transcriptase assay. The concentrated MuLV reached a much higher titer in the spleen in mice than the original one. The virus concentration assessed by p24 antigen for HIV was clearly higher than that of the original culture supernatant of HIV-infected cell lines. Since BMM hollow fibers trapped viruses by the sieving mechanism but not by adsorption, the viral particles were recovered by washing and the total live virus recovery rate was high, about 50%. Furthermore 60 min sufficed to handle 1000 ml of supernatant in the case of a filtration area of 0.03 m2. These results show that the BMM provides us with a rapid, safe and efficient method for concentrating live retroviruses.

Production of nonstructural proteins of hepatitis C virus requires a putative viral protease encoded by NS3

Hepatitis C virus (HCV) is a positive strand RNA virus with certain similarity to flaviviruses and pestiviruses. To examine the processing and possible assembly of HCV proteins, we constructed a recombinant vaccinia virus that expresses a full-length genomic RNA, infected chimp liver cells with the virus, and analyzed HCV-related protein products by immunofluorescent antibody staining and Western blot detection with mouse monoclonal antibodies. The putative core, envelope, and NS1 and NS3 proteins that yielded from this recombinant were 22, 32, 53 to 58, and 65 kDa in size, respectively. The NS4 protein was unexpectedly small, with an estimated molecular weight of 7 kDa, and the NS5 protein was found to be further cleaved into 52-kDa NS5a and 58-kDa NS5b proteins, the latter of which contains a hallmark of RNA replicase. A point mutation in the putative protease domain of NS3 resulted in a failure in the production of NS3, NS4, NS5a, and NS5b, but coexpression of NS3 restored the proper processing of these proteins, demonstrating that NS3, the putative viral protease, is essential for the production of these nonstructural proteins. Thus, HCV strikingly resembles pestiviruses in the size and the processing mode of the nonstructural proteins, particularly NS4 and NS5.

Effect of excess phenylalanine diet during pregnancy on fetal brain growth in rats

The effects of 10 and 20% casein diets containing 7% phenylalanine (Phe) during pregnancy on fetal brain growth were examined in rats. Control pregnant rats were fed the casein diets ad libitum or in restricted amounts. Total food intakes during 21-day period in the Phe excess groups decreased to about 50% of those of the liberally fed control groups. In control rats given 10 and 20% casein diets, fetal brain weights (Y, mg) were significantly and hyperbolically correlated to total food intakes (g/21 days), conforming to the following equations: Y = -10283/X + 130.5 (n: 13, r = 0.89, p < 0.001) and Y = -4396/X + 130.4 (n: 15, r = 0.68, p < 0.005), respectively. Similar plots for rats fed 10 and 20% casein diets with Phe fell below these lines, meaning that fetal brain growth was impaired by both the decreased food intake due to excess Phe (nonspecific effect) and the toxicity of excess Phe per se (specific effect). Total amounts of RNA and protein and protein/DNA ratio decreased in the fetal brain from excess Phe dams, suggesting that protein synthesis of brain cells was disturbed. This may be partly due to the disruption of normal patterns of free amino acids observed in the fetal brains. Reduction of total DNA was also seen in fetal brain from excess Phe groups, meaning impaired proliferation. From above findings we concluded that proliferation and hypertrophy were impaired in fetal brain from excess Phe dams.

Effect of dietary proteins on zinc bioavailability in pregnant rats

In order to clarify the effects of dietary proteins on zinc bioavailability during pregnancy, two experiments were carried out. In Experiment 1, changes in zinc retention due to pregnancy (difference in retention between pregnant and nonpregnant animals) during early-mid and late pregnancy were examined in rats fed 10 and 20% egg white diets. Total amounts of retained zinc due to pregnancy were about 1000 micrograms or slightly more, equal to the zinc content in the products of conception at term. However, extra zinc retention during late pregnancy ranged between only 20 to 40% of overall retention, suggesting that almost all zinc retained during early-mid pregnancy moved from the mothers to the fetuses near term. Zinc retention in early-mid and late periods of pregnancy was higher in pregnant than nonpregnant rats, due mainly to increases in intake and bioavailability. In Experiment 2, to examine the effects of quality and quantity of dietary proteins, pregnant rats were fed either 10 or 20% egg white (EW), whole egg (WE), casein (C) and soy protein isolate with or without methionine (SM and S, respectively) diets. Total zinc retention during pregnancy was affected by both zinc and nitrogen intakes, though the former effect was greater than the latter. Because rats fed the EW diets retained dietary zinc efficiently, a relationship between zinc retention (Y, microgram/100 g BW/21 d.) and zinc intake (X, microgram/100 g BW/21 d.) was also examined in the non-EW protein groups, resulting in the following regression equation: Y = 0.471X-1790 (n: 51, r = 0.81, p < 0.001). Dietary protein quality affected the food intake resulting in different zinc intake and retention during pregnancy. Zinc from EW diets was more available than from the other four protein diets, because similar plots for rats fed the 10 and 20% EW diets fell above this line. Reasons for efficient bioavailability of zinc in EW were discussed in connection with the forms of zinc in diets and the pancreatic or intestinal responses to ingested EW.

Effect of excess phenylacetate diet during pregnancy on fetal brain growth in rats

The effects of phenylacetate (PA) on fetal brain growth were examined in pregnant rats receiving a 20% casein diet with 1.0, 1.5, 2.0 or 2.5% PA. Control rats were fed the 20% casein diet ad libitum or restricted to daily consumption of 9 and 6 g. In experimental groups of rats total food intake during pregnancy decreased, however the decrease was not so large as we had expected. By plotting the fetal brain weight (Y, mg) against maternal food intake (X, g/21 days) in control groups the following hyperbolic regression equation was obtained: Y = -4243/X + 124.6 (n: 18, r = 0.80, p < 0.001). Similar plots for excess PA rats fell below this line, indicating that prenatal fetal brain growth was impaired by an excess in PA per se specifically, as well as by decreased food intake nonspecifically. Administering the excess PA diets resulted in decreases in total RNA, total protein and RNA/DNA ratio in the fetal brain, whereas total DNA was unchanged, showing the impairment of protein synthesis, not proliferation. No remarkable changes in concentration and pattern of free amino acids in maternal plasma in excess PA groups were observed. Using a relation between total food intake during pregnancy and fetal brain weight, the extent of specific and nonspecific effects of excess PA and phenylalanine on brain growth was compared.

A fluorescent carcinogen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in human lens

A fluorescent carcinogen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) has been identified in both human normal lenses and cataractous lenses. The total amounts of PhIP in normal lenses were 50.7 +/- 36.0 pg (n = 7) while those of PhIP in senile and diabetic cataractous lenses were 143 +/- 29.2 pg (n = 10) and 148 +/- 55.0 pg (n = 10), respectively. Although it was not possible to strictly compare the contents of PhIP among normal, senile and diabetic lenses, due to the limited numbers of normal lenses available, the mean total amounts of PhIP in normal lenses were the lowest among normal, senile and cataractous lenses when allowing for differences in age. Furthermore, there was a significant correlation between total amounts of PhIP in human lenses, and age of the lens, suggesting that the content of PhIP in human lens is increased with age. In all types of lenses, the concentrations of PhIP in the insoluble-protein fraction (pg mg-1 protein) were significantly higher than those in the water-soluble protein fraction. In addition, PhIP was formed when bovine lens was incubated at 37 degrees C under the presence of creatinine and glucose for various time periods, and the yield of PhIP during incubation was found to be time-dependent. The results from our study suggest that PhIP may be one of the age-related fluorogens in the human lens.

Nutritional improvements of soy protein isolate by different levels of methionine supplementation in pregnant rats

The effects of various levels (0, 0.3, 0.4, 0.5, 0.7, 1.0 and 1.5%) of methionine supplementation to a 10% soy protein isolate (SPI) diet were investigated in pregnant and nonpregnant rats in terms of body weight gain, food efficiency, net protein utilization (NPU), growth of the conceptuses and free methionine concentration in the dam's plasma. Supplementation of 0.3 to 0.7% methionine resulted in increases in the weights of the body, fetus and placenta and improvements of food efficiency and NPU in both groups of rats. The extents of increases or improvements of these parameters were more in pregnant rats than in nonpregnant rats, though they were similar in each group independent of the dietary methionine level. No beneficial effects on body weight gain, food efficiency or reproductive performance were observed in rats fed diets with 1.0 or 1.5% methionine. The concentrations of free methionine in the plasma were increased by methionine supplementation to the diet and were consistently higher in nonpregnant rats than in pregnant rats at each level of methionine supplementation. From these results, we proposed that a level of 0.5% methionine (intermediate between 0.3 to 0.7%) is optimal for supplementing 10% SPI diet for rats. The appropriateness of this level is discussed in relation with the methionine equipment of growing rats.

Nucleic acids induce the formation of a carcinogen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in a model system

Effects of nucleic acids on the formation of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) were studied in a model system. When a mixture of a certain amount of DNA or RNA, creatinine (1 mmol) and phenylalanine (1 mmol) in 10 ml of 50 mM phosphate buffer, pH 7.4, was heated at 60 degrees C for 4 weeks in a screw-capped vial, PhIP was produced, and the yield of PhIP was dependent on the heating time as well as the dose of nucleic acid added to the mixture. However, PhIP was not detectable in the mixtures without the presence of nucleic acids. Both deoxyribonucleotides and ribonucleotides tested induced the formation of PhIP under the presence of phenylalanine and creatinine, although bases of nucleic acids such as adenine and guanine did not induce PhIP formation. Moreover, we confirmed that 2-deoxy-D-ribose as well as D-ribose induced the formation of PhIP in the presence of creatinine and phenylalanine. These results indicate that nucleic acids can induce the formation of PhIP in the presence of creatinine and phenylalanine in the model system. Our data also suggest that pentose in nucleic acids may participate in PhIP forming reactions.

Detection of the carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in beer and wine

A carcinogen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), was measured in beer and wine by HPLC. PhIP was found to be present in all brands of beer and wine analyzed. The concentrations of PhIP in beer and wine were 14.1 +/- 6.18 ng/l (mean +/- SD, n = 11) and 30.4 +/- 16.4 ng/l (n = 10) respectively.

Detection of a carcinogen, 2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine, in airborne particles and diesel-exhaust particles

A carcinogen, 2-amino-1-methyl-6-phenylimidazo [4,5-b]-pyridine (PhIP), has been measured in airborne particles, diesel-exhaust particles, and incineration ash from garbage-burning plants. PhIP was found in all kinds of samples. In the light of the present results, together with the previous findings that PhIP was present in cooked foods and cigarette smoke, PhIP is likely to be an ubiquitous environmental pollutant. These observations also suggest that PhIP may be formed through the combustion process.

The effects of hyperthermia on the spinal cord

This study was conducted to obtain information about the critical temperature of the spinal cord in hyperthermia produced by radiofrequency waves applied to the spine. The first component of the spinal cord evoked potential was analyzed as an indicator of spinal cord function. The spinal cords were heated by radiofrequency waves to a maximum of 47 degrees C momentarily or for 30 minutes. The temperatures were measured with a thermosensor in the epidural space. In momentary heating, the reductions in amplitude were almost parallel with the increases in temperature. In maintained heating for 30 minutes, at 44 degrees C and below, the amplitudes decreased by one-quarter to three-quarters of the control value in the first 5 minutes and recovered to over three-quarters of the control value in 30 minutes. The amplitudes returned to almost the control value after restoration of normal spinal cord temperatures. At 45 degrees C and above, however, the amplitudes were prominently reduced or disappeared in the first 5 minutes and remained depressed during the remainder of the heating. On normalizing the temperature, the amplitudes did not return to the control value. These results suggest that 44 degrees C in the epidural space is the highest tolerable temperature for normal spinal cord function.