Differences in interleukin 1 (IL-1), IL-6, tumor necrosis factor and IL-1 receptor antagonist production by human monocytes stimulated with muramyl dipeptide (MDP) and its stearoyl derivative, romurtide

The immunostimulatory reagents muramyl dipeptide (MDP) and its stearoyl derivative romurtide [MDP-Lys(L18)] were assessed for cytokine inducing activity in human monocytes. Both MDP and romurtide stimulated the production of interleukin-1 (IL-1), IL-6, tumor necrosis factor (TNF) and IL-1 receptor antagonist (IL-1Ra). Kinetics study indicated that IL-1, TNF and IL-1Ra were induced after 4 h stimulation but IL-6 was produced at a later phase. Romurtide induced these cytokines for longer period that MDP. Dose-response study indicated that romurtide was far more potent than MDP in induction of IL-1, IL-6 and TNF. Although the magnitude of the IL-1 and IL-6 induction was almost the same, that of TNF induction was greater in romurtide-stimulated monocytes than in MDP-stimulated cells. Among IL-1, IL-1 beta appeared to be a major product. In contrast to other cytokines, IL-1Ra was induced by MDP and romurtide in a similar dose and time dependent manner with similar magnitude of response. These studies indicate that MDP and romurtide, especially romurtide, are very potent inducers of both immunostimulatory and immunosuppressive cytokines by human monocytes but with different efficacy and kinetics.

A complete cDNA sequence for core I protein subunit of human ubiquinol-cytochrome c reductase

Core I protein is the largest subunit of ubiquinol-cytochrome c reductase. We have isolated a complete cDNA clone of 1575 bp encoding the precursor to this protein by screening a human fibroblast cDNA library. Nucleotide sequence comparison showed that the human core I protein cDNA is about 85% homologous with the reported bovine counter part but with a large difference in the length of coding region which consists of 480 amino acids in human and 362 amino acids in bovine. Human core I protein is presumed to contain a presequence of 34 amino acids. Amino acid sequence alignment study showed that the predicted human core I protein has a significant homology with other members of matrix processing peptidase (MPP) and processing enhancing protein (PEP) family.

Lymphoid interstitial pneumonia as a pulmonary lesion of idiopathic plasmacytic lymphadenopathy with hyperimmunoglobulinemia

A case of idiopathic plasmacytic lymphadenopathy with hyperimmunoglobulinemia is reported. A 71-year-old man was admitted to the hospital because of the abnormal shadow on chest roentgenogram. Chest X-ray taken on admission showed remarkable diffuse infiltration and pleural thickening. Laboratory examinations revealed an elevated total protein level of 10.1 g/dl, and a gammaglobulin level of 7.0 g/dl including 6,790 mg/dl IgG. Mediastinal lymphadenopathy was observed on a chest CT. The patient underwent open lung biopsy. Heavy infiltration of lymphocytes and plasma cells were seen in the moderately fibrotic pulmonary interstitium. LIP was diagnosed. Lymph node biopsy was also performed. Follicular hyperplasia with prominent germinal centers and plasma cell proliferation in the interfollicular area were seen. Treatment with prednisolone resulted in an improvement in the chest X-ray findings, as well as a diminished polyclonal hypergammaglobulin level.

Reduction of the severity of bronchial hyperresponsiveness by the novel leukotriene antagonist 4-oxo-8-[4-(4-phenyl-butoxy)benzoylamino]-2- (tetrazol-5-yl)-4H-1-benzopyran hemihydrate

There is much evidence that the cysteinyl-leukotrienes (C-LTs) are important in the pathogenesis of asthma. The clinical effect of a new leukotriene antagonist, ONO 1078 (4-oxo-8-[4-phenylbutoxy)benzoylamino]-2-(tetrazol-5-yl)-4H- 1-benzopyran hemihydrate, CAS 103177-37-3) on symptoms, pulmonary lung function and bronchial hyperresponsiveness was evaluated in patients with bronchial asthma. Eleven patients were treated for 24 weeks with 450 mg of ONO 1078 twice daily. The score of asthma symptom severity and the number of inhaled procaterol were significantly reduced after 2 weeks of ONO 1078 treatment and remained decreased for another 22 weeks. Their FEV1 and PC20 to histamine significantly improved 12 and 24 weeks after ONO 1078 treatment. The effectiveness of ONO 1078 suggests that the C-LTs play an important role in the pathogenesis of asthma. ONO 1078 might help to favorably modify the pathophysiologic condition in patients with bronchial asthma.

Differential production of interleukin 1 (IL-1), IL-6, tumor necrosis factor, and IL-1 receptor antagonist by human monocytes stimulated with Mycobacterium leprae and M. bovis BCG

Human blood monocytes cultured in various serum conditions were stimulated with Mycobacterium leprae or M. bovis BCG and their cytokine-inducing abilities were compared. BCG, either live or killed, induced production of interleukin 1 (IL-1), IL-6, tumor necrosis factor (TNF), and IL-1 receptor antagonist (IL-1ra). Live BCG at a lower bacterial number was more potent than killed BCG in the induction of IL-6 and TNF. In contrast to BCG, killed M. leprae induced few cytokines except for IL-1ra. Similar results were obtained when monocytes were cultured in the presence of untreated or heat-inactivated fetal bovine serum (FBS). When FBS and human serum (HS) were compared and the effect of heat inactivation was investigated, monocytes in HS produced the most cytokines, then those in FBS, irrespective of heat inactivation, and those in heat-inactivated HS produced the least cytokines. There were no differences between live and killed M. leprae, and BCG were far more potent than M. leprae in all of our experimental conditions, indicating that the poor cytokine (IL-1, IL-6 and TNF)-inducing ability of M. leprae was not due to their viability. Cytokine production was partially in parallel with the phagocytosis of the mycobacteria. These results suggest that M. leprae favor their infection by evoking little host reaction through the induction of only low levels of immunostimulatory or proinflammatory cytokines but a substantial amount of immunosuppressive cytokine.

Activin A: serum levels and immunohistochemical brain localization in rats given diets deficient in L-lysine or protein

When a L-lysine (Lys)-deficient diet is given to rats, Lys in plasma and brain declines and rats will then select a Lys solution from among other L-amino acids (AAs). The recording of single-unit activity in the lateral hypothalamic area of these rats suggested that neural plasticity occurred, specifically responding to the deficient nutrient, Lys, centrally and during ingestion of AA. Possible neurotrophic factors in serum from rats with or without deficiency of either protein or Lys was assayed by Hydra japonica. An increase in serum inhibin and activin A was observed in rats fed a Lys-sufficient and nonprotein diet, respectively. However, serum activin A-like activity was severely suppressed under Lys deficiency. Additionally, the immunohistochemical distribution of activin A in the brain was found in the nucleus tractus solitarius, the area postrema, and the arcuate nucleus. These facts indicate that ingestion of Lys-deficient or nonprotein diet caused a change in serum levels of activin A as a possible neurotrophic factor. This release may elicit plasticity in the sensitivity of neurons to deficient AA in the nuclei that could selectively drive ingestive behavior for its particular AA (e.g., Lys) to maintain AA homeostasis.

[In vitro susceptibilities of Mycobacterium avium and Mycobacterium intracellulare to new macrolides, new quinolones, and antituberculous drugs on Dubos agar medium]

Mycobacterium avium and M. intracellulare were isolated from the sputum of patients infected with atypical mycobacteria using 1% Ogawa medium and identified by the DNA probe test. Then the MICs of various kinds of drugs against these mycobacterial species were determined on Dubos agar medium, and the drug susceptibilities were also determined on 1% Ogawa medium in parallel. The drugs tested were new macrolides, such as clarithromycin (CAM) and roxithromycin (RXM), new quinolones, such as ofloxacin (OFLX) and ciprofloxacin (CPFX), and antituberculous drugs, such as isoniazid (INH), rifampicin (PFP), streptomycin (SM), and ethambutol (EB). The MICs of the drugs tested, especially those of CAM, OFLX, and RFP, when determined on Dubos agar medium, were generally lower against M. intracellulare than against M. avium. The susceptibilities of the mycobacterial isolates tested to RFP and SM determined on Dubos agar medium were markedly different from those determined on 1% Ogawa medium. Such discrepancies may be accounted for by absorption of these drugs to the egg medium and instability of RFP in the egg medium. Overall, our results indicate that the new macrolides and new quinolones are effective against atypical mycobacteria.

Aging-associated deletions of human diaphragmatic mitochondrial DNA

It is known that respiratory function deteriorates with age. Endogenous damage to DNA is thought to contribute to the aging process. The mitochondrial oxidative phosphorylation system, a bio-engine, consists of five complexes, and 13 subunits of those complexes are biosynthesized from information encoded in mitochondrial DNA. Mitochondrial DNA is shown to have a much higher mutation rate than nuclear DNA. We examined the diaphragms obtained at autopsy from 34 humans, 23 men and 11 women, ranging in age from 25 to 85 yr, for mitochondrial DNA deletions using the polymerase chain reaction method. Multiple mitochondrial DNA deletions were detected particularly among the elderly; the number of deletions in those over age 70 was significantly higher than in those under age 40. The occurrence of a 3.4-kbp deletion of mitochondrial DNA increased with age, i.e., 0% of those under age 30, 20.0% of those in their forties, 25.0% of those in their fifties, 28.6% of those in their sixties, 72.7% of those in their seventies, and in all of those over age 80. The mutation was based on the directly repeated sequence, 5'-TCACCCC-3', which exists in both the CO3 gene and the ND5 gene. Replication impairment occurred at that directly repeated sequence, which caused the elimination of a genome between the CO3 gene and the ND5 gene, and information for biosynthesis of four subunits in complex I (ND3, ND4L, ND4, and ND5), one in complex IV (CO3), and five transfer RNA genes was missing.(ABSTRACT TRUNCATED AT 250 WORDS)

Age-related decrease in respiratory muscle mitochondrial function in rats

The purpose of this study was to elucidate the effects of aging on diaphragmatic mitochondrial function. Diaphragm mitochondria were prepared from specific pathogen-free rats aged 7 wk (n = 7), 35 wk (n = 7), and 55 wk (n = 7). The activities of various portions of the mitochondrial electron transport chain, i.e., complexes I, II, III, and IV, were measured enzymatically. The specific activities of complex I decreased significantly (P less than 0.01) in 35-wk-old rats (726 +/- 90 nmol/min/mg protein) compared with 7-wk-old rats (1,018 +/- 121), and the decrease was more remarkable in 35-wk-old rats (565 +/- 64; P less than 0.01 versus 35-wk-old). The activities of complex IV also decreased significantly (P less than 0.01) in 55-wk-old rats (1,222 +/- 191) compared with 7-wk-old rats (1,797 +/- 208); however, no significant changes in complex IV activities between 7-wk-old rat and 35-wk-old rats were observed. In contrast, the activities of complex II and III were not affected by aging. Limb muscle, heart, and liver mitochondria were also prepared from the same rats. The same tendency was observed in limb muscle mitochondria; however, in heart and liver mitochondria, activities of all four complexes were not changed in rats of all age groups. These results indicate that vulnerability of mitochondrial electron transport chain to aging differs from organ to organ and that it also differs from portion to portion in the electron transport chain and the most vulnerable site was complex I.(ABSTRACT TRUNCATED AT 250 WORDS)

Age-associated accumulation of 8-hydroxydeoxyguanosine in mitochondrial DNA of human diaphragm

This is the first report that age-associated accumulation of 8-hydroxydeoxyguanosine (8-OH-dG) does occur in human mitochondrial DNA (mtDNA) in muscle of diaphragm. We extracted mtDNA from human diaphragm muscles from differing age groups, and determined the amount of 8-OH-dG by ultramicro-high performance liquid chromatography/mass-spectrometry system. With the same specimen, multiple deletions of mtDNA were detected by electrophoresis after amplification by the polymerase chain reaction method. In subjects below age 55, the level of 8-OH-dG in mtDNA was below 0.02% of the total deoxyguanosine (dG), whereas, in subjects over age 65, the level of 8-OH-dG increased with age at a rate of ca. 0.25% per 10 years, reaching 0.51% at age 85. Moreover, a concomitant increase in multiple deletions was detected with the increase in age. These results suggest that, in younger diaphragms, replication of mtDNA dilutes out 8-OH-dG being not detectable. In the elderly subjects aged over 65, the replication rate might be slowed down leading to the accumulation of 8-OH-dG in mtDNA, which would accelerate the age-associated multiple deletions of mtDNA observed among the subjects.

Immunohistochemical localization of a glycoprotein, GP80, in the outermost layer of the developing endosperm of immature seeds of carrot

A glycoprotein (GP80) from the immature fruits of carrot (Daucus carota L.) plants was purified through the sequential application of salt extraction, (NH4)2SO4 precipitation, chromatography on columns of concanavalin A-Sepharose, hydroxylapatite, and boronate, and electroelution, with subsequent sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Its apparent relative molecular mass (Mr) was estimated to be 80 k by both SDS-PAGE and gel filtration at high ionic strength. The Mr of the polypeptide portion was estimated to be 74 k after deglycosylation by trifluoromethanesulfonic acid (TFMS). Antibodies were produced by immunizing rabbits with purified and deglycosylated GP80. Using immunoblotting of total protein extracts from each organ and tissue GP80 was detected only in immature seeds. It appeared at 4 d after flowering (DAF), accumulated until 15 DAF, then its level suddenly decreased and it disappeared completely at 23 DAF. Another glycoprotein, with an Mr of 78 k (GP78), cross-reacted with GP80-specific antibodies. GP78 appeared at 17 DAF and disappeared at 37 DAF. Histochemical examination of fruits using Sudan Black B and periodic acid-Schiff reagent (PAS) showed that the appearance of GP78 coincided with the rapid filling of the central cavity with endosperm cells, which have cell walls and contain lipid storage granules. In immunohistochemical studies, both GP80 and GP78 were found at the outermost layer of the developing endosperm.

Appetite and taste preference in growing rats given various levels of protein nutrition

The cephalic gustatory stimuli during a meal yield nutritional information and aid in the efficient control of homeostasis. This study was focused on either appetite for flavored food or feeding behavior in growing male Sprague-Dawley rats under various states of protein nutrition. In fasted rats, endogenous protein degradation was suppressed by ingestion of glucose that was sufficient to meet energy needs. The decrease in the amount of diet intake was compensated by sugar ingestion, except for sucrose. Rats that ingested sucrose exceeded 115% of total energy intake, compared to ingestion of saccharin as a control. Appetite and meal size are primarily dependent upon the dietary protein level, whether it was beyond normal requirements or not and, thus, flavoring by certain taste material is effective for a diet sufficient in protein, but not for a deficient one. In addition, rats fed a diet containing amino acids preferred saccharin and monosodium L-glutamate (MSG) and grew normally. But, when L-tryptophan-deficient diet was offered, the preference for tryptophan was elicited, and then MSG intake was elevated and their growth became normal. However, preference for saccharin never occurred because the level of tryptophan in blood fluctuated and was not maintained within normal limits. The strong preference for sweetness that is evoked by starvation is directly regulated by the negative energy balance. The animals' primary concern was energy intake and their second concern was protein nutrition, regardless of flavoring.

Amino acid and NaCl appetite, and LHA neuron responses of lysine-deficient rat

Rats' preferences for amino acids and NaCl in their drinking behavior were noted when they were fed either a control diet of gluten plus 20% purified egg protein, or (same rats, different time) a lysine-deficient diet. In control, the order of the rats' preferences was arginine greater than saline greater than monosodium L-glutamate (MSG, umami) greater than glycine greater than water greater than threonine greater than histidine greater than lysine. When fed a lysine-deficient diet the order of preference was lysine greater than saline greater than MSG greater than glycine greater than threonine greater than water greater than arginine greater than histidine. To relate neural activity with preference for amino acids and NaCl, activity of lateral hypothalamic (LHA) neurons was recorded during ingestion of MSG, lysine, arginine, glycine, saline, glucose, or water by the control and lysine-deprived condition, following a different cue tone. When the diet was lysine deficient, some neurons responded specifically to lysine ingestion. More neurons responded nondifferentially during licking in control, and responded to lysine, but fewer to other amino acid ingestion during lysine deficiency. Responses to cue tone were associated with those during licking. The present results suggest that preference for deficient amino acids might be mediated in the LHA.

Taste preference and protein nutrition and L-amino acid homeostasis in male Sprague-Dawley rats

Changes in taste preference were investigated in a choice paradigm using rats under various states of protein nutrition. A preference for the umami taste substances, monosodium L-glutamate (MSG) with or without 5'-ribonucleotide (5'-guanosine monophosphate), was induced when dietary protein was within the normal range, but a preference for NaCl occurred under its marginal deficiency. A preference for both NaCl and glycine was induced under severe protein malnutrition, possibly reflecting the body's negative nitrogen balance. The strength of this preference paralleled the body's requirement for protein, and thus, like the protein requirement for normal growth, declined with age. When animals with L-lysine (Lys) deficiency consumed a Lys solution and began to grow normally, their intake of taste stimulus solutions changed from preferring NaCl and glycine to preferring MSG. The regulatory mechanism of preference for L-amino acid (AA) in rats deficient of an essential AA was related to the pattern of AA in plasma and brain. Data suggest that umami taste perception plays an important role in protein metabolism, and in maintenance of AA and ammonia homeostasis within normal limits.

Involvement of 5-hydroxytryptamine 3 receptors in regulation of interdigestive gastric contractions by motilin in the dog

The effects of IV injection of 5-hydroxytryptamine 3 receptor antagonists (BRL 43694 and GR38032F) on gastrointestinal contractile activity were studied in dogs with vagally denervated fundic pouch in the conscious state by means of chronically implanted force transducers in the gastrointestinal tract and the pouch. In the interdigestive state, 5-hydroxytryptamine 3 receptor antagonists (0.01-0.1 mg/kg), if given during phase III contractions, instantly and dose-dependently inhibited the spontaneous and motilin-induced phase III contractions in the intact stomach and altered the duodenal phase III contractions to a pattern of continuous contractions, the contractile force which was 65% of the spontaneous phase III contractions in the duodenum and caused immediate caudad migration of phase III contractions along the small intestine. However, the spontaneous and motilin-induced phase III-like contractions in the denervated pouch were not affected at all by 5-hydroxytryptamine 3 receptor antagonists. When 5-hydroxytryptamine 3 receptor antagonists (0.1-3.0 mg/kg) were given during the phase I period, they did not directly stimulate gastrointestinal contractions. The cyclic fluctuation of the plasma motilin concentration with phase III activity in the stomach was also not influenced by 5-hydroxytryptamine 3 receptor antagonists, but the next phase III contractions in the stomach were inhibited. During the digestive state, however, 5-hydroxytryptamine 3 receptor antagonists (0.1-3.0 mg/kg) did not influence contractile activity in the gastrointestinal tract and in the vagally denervated fundic pouch. On the basis of recent pharmacological studies showing that the distribution of 5-hydroxytryptamine 3 receptors is recognized in the area postrema, peripheral neurons of vagal afferents, and the enteric nervous system, the results of the current study provide a basis for a hypothesis that 5-hydroxytryptamine 3 receptor antagonists are most likely to block motilin-induced signals at 5-hydroxytryptamine 3 receptors on the vagal afferents. In conclusion, the present findings suggest the possible involvement of 5-hydroxytryptamine 3 receptors on vagal afferents especially in terms of endogenous release of acetylcholine in the control of interdigestive phase III activity in the stomach by motilin.

Coexisting thymic carcinoid tumor and thymoma

Thymic carcinoid tumors are unusual neoplasms that are different from thymomas. We report a case of coexisting thymic carcinoid tumor and thymoma associated with myasthenia gravis. The clinicopathological findings are discussed with a review of the literature.

[A comparative study on the responses of blood vessels of oral mucosa to thermal stimulation in dentulous and edentulous subjects]

The purpose of this experiment was to clarify the characteristic changes of vasculature in edentulous alveolar mucosa and the effect of wearing a complete denture during sleep. Thermal stimulations were applied to the oral mucosa of five normal subjects and five completely edentulous patients and the responses of blood vessels were observed using both Impedance Plethysmography (IMP) and Reflection Photoelectric Plethysmography (RPP). Quantitative comparisons were made between edentulous patients and dentulous normal subjects, and between patients wearing complete dentures during sleep and those who do not. The following results were obtained. 1) The responses of blood vessels were divided into four groups. Type 1 showed dilatation in IMP and RPP. Type 2 showed dilatation but had late initial rising in IMP. Type 3 showed initial contraction in either or both IMP and RPP, and followed by dilatation few seconds later. Type 4 showed no changes in RPP but dilatation in IMP. 2) There was definite difference between edentulous and dentulous subjects in the frequency of exhibition of each type. Especially for the edentulous patients type 4 was observed in all stimulation temperature. 3) For the dentulous subjects there were more cases showing responses of RPP in digital apex than those do not. This was most conspicuous at the 50 degrees C stimulation. However for the edentulous patients there were about equal number of each cases. 4) The responses of blood vessels for both dentulous and edentulous subjects became greater and blood volume increased both with time at each temperature and as the stimulation temperature were raised. However the increase in the response was greater for the edentulous patients when the stimulation temperature was raised from 0 degrees C to 50 degrees C. 5) The responses of blood vessels became greater after two weeks when complete dentures were worn during sleep at night. And when dentures were not worn during sleep the responses decreased to a level lower than what it used to be after three weeks. 6) From the above results it was suggested that oral mucosa of the edentulous patients were losing their sensitivity due to wearing complete dentures and were not receiving as much effect of the contractile control from body as the dentulous subjects. It was also suggested that wearing denture during sleep at night cause inflammation of oral mucosa and increase the metabolism of tissue in edentulous patients.

Analysis of rotation centers of various mandibular closures

Wax interocclusal records of five subjects made during three types of mandibular closing movement at various degrees of jaw opening were successively placed between mandibular and maxillary casts that were mounted on an articulator. Recording pins inserted into the lateral sides of the casts were used to record the amount of movements. The rotation centers were then calculated and the following results were obtained. (1) For the terminal hinge closure in which the mandible was guided by the chinpoint, no statistically constant rotation center was observed. (2) For the most retruded closure of the mandible in which each subject was asked to make the most retruded position by his own effort, a constant rotation center was found in two of five subjects. (3) For habitual closure of the mandible no constant rotation center was observed, and where the interocclusal distance was less than 1 mm the mandible seemed to close perpendicular to the occlusal plane.

Dissociation of various biological activities of Clostridium perfringens alpha toxin by chemical modification

The effect of N-acetylimidazole, tetranitromethane, maleic anhydride and N-ethylmaleimide on various biological activities of Clostridium perfringens alpha (alpha)-toxin was investigated. Treatment of the toxin with N-acetylimidazole, tetranitromethane or maleic anhydride resulted in significant reduction of lethal, hemolytic and platelet-aggregating activities and phospholipase C activity (EY activity), as measured by increased turbidity in egg yolk emulsions. However, EY activity was more resistant to these reagents than lethal, hemolytic or aggregating activities. Phospholipase C activity (PN activity) as measured by hydrolysis of p-nitrophenylphosphorylcholine was retained after treatment with N-acetylimidazole, tetranitromethane or maleic anhydride. The activities of the toxin were not inactivated by treatment with N-ethylmaleimide. These data suggest that alpha-toxin contains multiple sites for biological activities of the toxin.

Erythromycin and its derivatives with motilin-like biological activities inhibit the specific binding of 125I-motilin to duodenal muscle

Erythromycin, one of the macrolide antibiotics, and its derivatives had been found to mimic actions of exogenous motilin, a gastrointestinal peptide hormone. We found that some of the macrolide compounds inhibited the specific binding of 125I-motilin to rabbit duodenum muscle at 15 C in a dose-dependent fashion. The inhibitory activity of several macrolides examined did not relate to their antibacterial activity but to their motilin-like activity. A 50% inhibition by EM536, a non-antibacterial erythromycin derivative with the highest motilin-like activity, was obtained at 3-40 nM and little higher than that of non-radioactive motilin (5-6 nM) under the present conditions. The results suggest that erythromycin and its derivatives mimic physiological actions of motilin by acting as agonists for a motilin receptor.

Mealing and related hormone release suppress hypothalamic lesions of neonatal mice by L-glutamate

Neonatal mice, under fasting conditions, are susceptible to the development of lesions in the arcuate nucleus (AN) of the hypothalamus, with high doses of monosodium L-glutamate (MSG). Feeding of nutrients (e.g., sugars and L-amino acids) has been shown to have a protective effect against the development of these lesions. The purpose of these studies was to elucidate the mechanism of this protective effect. Histopathologic examination of lesions of the AN demonstrated that feeding of weaning mice before subcutaneous administration of toxic doses of MSG suppressed the development of these lesions, as compared to fasted controls. Similarly, the number of necrotic cells in the AN of neonates administered toxic doses of MSG subcutaneously was reduced when D-glucose and L-arginine were administered orally. Atropine obliterated the protective effect of D-glucose. Pretreatments consisting of gastric inhibitory polypeptide (GIP) + oral D-glucose had a protective effect of higher potency than GIP alone. Pretreatments with insulin, anorexigenic peptide (pyroGlu-His-Gly), cholecystokinin, glucagon, bombesin, and substance P (in decreasing order of effectiveness) demonstrated a protective effect against the AN lesion in neonates, whereas somatostatin and beta-endorphin had no effect. Results suggest that the protective effect of nutrients may in part be due to the stimulation of peptide hormone release during the postabsorptive phase. It is postulated that the effect of entero-pancreatic hormone, especially insulin, is to enhance the tolerance of AN neurons of neonatal mice to the toxic dose of L-glutamate.

Effect of mealing on plasma and brain amino acid, and brain monoamine in rats after oral aspartame

Aspartame (APM; L-aspartyl-L-phenylalanine methyl ester) was investigated for its ability to alter brain amino acids and monoamines in overnight fasted rats allowed to consume commercial diets for 60 minutes. In addition, the effects of mealing on the changes in plasma and brain amino acids and brain monoamines induced by glucose and/or insulin, and known pharmacologically active compounds, were studied. The consumption of the commercial chow largely prevented changes in blood glucose and amino acids, and brain amino acids and the monoamines dopamine, norepinephrine and serotonin that might be expected to occur following glucose with or without insulin. Feeding failed to prevent changes in the above parameters when 5-hydroxy-tryptophan, p-chlorophenylalanine and reserpine were administered. The oral administration of up to 250 mg/kg BW APM with water or glucose followed by free feeding failed to alter brain monoamines. These studies demonstrate the potent ability of food to normalize biochemical parameters in blood and brain that otherwise might occur, and clearly show the lack of effect on brain monoamine levels of abuse doses of APM when administered with food.

Dietary aspartame with protein on plasma and brain amino acids, brain monoamines and behavior in rats

Aspartame (APM; L-aspartyl-L-phenylalanine methyl ester), was investigated for its ability to alter levels of the large neutral amino acids and monoamines in overnight fasted rats allowed to consume meals with or without protein for two hours. Additionally, the possible long term behavioral consequences of APM in 25% casein diets with or without 10% sucrose were determined. Acute APM ingestion increased both plasma and brain phenylalanine and tyrosine levels, but brain tryptophan levels were not altered regardless of dietary protein. Brain norepinephrine and dopamine levels were unaltered by any of the diet while serotonin levels were slightly increased when a protein-free diet was consumed. But APM and/or protein ingestion minimized this increase of brain serotonin levels as much as controls. Chronic APM ingestion failed to influence diurnal feeding patterns, meal size distributions, or diurnal patterns of spontaneous motor activity. The chronic ingestion of abuse doses of APM produced no significant chemical changes in brain capable of altering behavioral parameters believed to be controlled by monoamines in rats.

Purification and characterization of alpha-glucosidases produced by Saccharomyces in response to three distinct maltose genes

alpha-Glucosidases or maltases (EC 3.2.1.20) were purified to electrophoretic homogeneity from a respective strain of Saccharomyces cerevisiae which carries a single MAL gene, either MAL alpha, MAL beta, or MAL gamma, using gluconate-Sepharose affinity chromatography and isoelectrofocusing. Of these maltases, two types of maltase were obtained from the MAL gamma strain, the pI values of which were 5.6 and 5.9. From the MAL alpha and MAL beta strain was obtained only one type of maltase with the pI at 5.6 which was identical to one of the maltases from the MAL gamma strain. These four maltases possessed the same properties, except for pI. They were monomers with molecular weights of between 66 000 and 67 000. With regard to the substrate specificity, they hydrolyzed maltose and sucrose exclusively but not alpha-methylglucoside nor maltooligosaccharide. They did not differ in immunological properties.

Effect of water restriction on the development of hypothalamic lesions in weanling rodents given MSG. I. Drinking behaviour and physiological parameters in mice (Mus musculus)

Deprivation of water overnight (ON: 19.00-09.00 h) induced approx. 20% haemoconcentration in weanling ICR strain mice and resulted in avid consumption of fluid offered for 30 min subsequently, with delayed restoration of serum osmolality and sodium to normal levels in those offered 8% w/v monosodium L-glutamate monohydrate (MSG) aqueous solution. Neuronal necrosis of the arcuate nucleus of the hypothalamus was found in 12/180 dehydrated mice deprived ON and subsequently consuming 3.0 g or more MSG/kg body weight offered hypertonic MSG solution as the sole source of drinking water. The lesions were less severe than in mice given MSG s.c. or by forced intubation. Mice deprived ON and subsequently consuming MSG solution with water in a free choice experiment, and those deprived during daytime (DT: 07.00-21.00 h) and subsequently consuming MSG solution, with or without water, developed fewer and less severe lesions than did mice deprived ON and subsequently consuming MSG solution solely. The provision of other nutrients (e.g. glucose, arginine) reduced glutamate-induced hypothalamic lesions and elevation of plasma L-glutamate. The findings are in accord with earlier observations that hypothalamic lesions do not result even in this most susceptible species from the 'voluntary' consumption of MSG by physiologically normal animals. No lesions were produced even in mice deprived of food and water ON and subsequently consuming up to 7.3 g MSG/kg body weight in diet and in soup.

Pyroglutamate kinetics and neurotoxicity studies in mice

Plasma and brain kinetics of L-glutamic (GA) and L-pyroglutamic (PY) acids were studied after oral administration of monosodium glutamate (MSG) or pyroglutamate to adult mice. Oral MSG (0.5 g/kg) increased plasma GA and PY levels 4.5 and 1.8 times, respectively. A small increase in brain PY (1.3 times the basal level) but not in brain GA, was observed. Oral administration of pyroglutamate (0.5 g/kg) increased plasma PY levels 56 times in adult mice and 69 times in infant mice. No lesions in the arcuate nucleus of the hypothalamus were observed when pyroglutamate was administered orally to infant mice at doses of 2 and 4 g/kg.

Effect of water restriction on the development of hypothalamic lesions in weanling rodents given MSG. II. Drinking behaviour and physiological parameters in rats (Rattus norvegicus) and golden hamsters (Mesocricetus auratus)

No hypothalamic lesions were found in weanling Sprague-Dawley (SD) rats or in golden hamsters deprived of water and/or food overnight (ON 19.00-09.00 h) and offered monosodium L-glutamate monohydrate (MSG) in up to 10% solution for 30 min subsequently. ON restriction of water resulted in haemoconcentration, with elevation of haematocrit, plasma protein, electrolytes and osmolality in SD rats. Water-restricted rats avidly consumed large volumes of concentrated MSG solution and showed further evidence of haemoconcentration, with delayed restoration of plasma sodium and with high plasma glutamate, but did not develop lesions at up to 5.4 g MSG/kg b.w. Hamsters deprived of water ON consumed smaller volumes of MSG in aqueous solution than did SD rats, and in them no hypothalamic lesions were observed. That SD rats and golden hamsters, which are susceptible to hypothalamic lesions from the parenteral administration of high doses of MSG, did not develop lesions following the voluntary intake of MSG in aqueous solution, even under conditions of severe thirst, is further evidence of the safety of MSG as a food ingredient.

Drinking behavior and the development of hypothalamic lesions from aspartame ingestion in water-restricted weanling mice

Wealing mice that had been deprived overnight of water, or of water and diet, were offered a solution containing L-aspartyl-L-phenylalanine-methylester (APM) or monosodium L-aspartate monohydrate (MSA) as the sole source of drinking water, and/or a diet containing large amounts of APM and/or MSA for 30 min, and were killed subsequently. Only those animals exposed to concentrated (6.64% W/V) MSA solutions developed neuronal lesions in the hypothalamic arcuate nuclei. Those offered MSA in the diet only, or APM either in the diet and/or in solution, failed to develop such lesions. Apparently water-restricted weanling mice lose their ability to regulate subsequent drinking behavior, and consume hyperosmolar MSA or APM solutions whose osmolarity or sweetness would be aversive to humans. Such animals are unsuitable for the safety evaluation of APM.

Biochemical studies of taste sensation. IX. Enhancement of L-[3H]glutamate binding to bovine taste papillae by 5'-ribonucleotides

The interaction of the taste substance monosodium L-glutamate with taste receptors has been investigated. Binding of L-[3H]glutamate was measured to preparations of bovine circumvallate (taste) papillae (type I preparation) and to control tongue epithelial preparations (type II preparation) devoid of taste receptors. Binding is operationally defined using a membrane filtration assay. Substantially greater binding occurred to the type I preparation than to the type II preparation, and the binding to the type I preparation showed evidence of saturation. The apparent Kd of L-glutamate was estimated to be in the range of 20--30 mM. The unique taste effect of L-glutamate was considered to depend importantly on its demonstrated synergism in combination with certain 5'-ribonucleotides. A several-fold enhancement of binding of L-[3H]glutamate occurred in the presence of certain 5'-ribonucleotides. 5'-GMP, 5'-IMP and 5'-UMP each increased the binding of L-[3H]glutamate, while 5'-XMP, 5'-AMP and 5'-CMP did not. None of these nucleotides affected the lower level of binding to the type II preparation. Neither the free bases, adenine and guanine, their nucleosides nor their di- or triphosphonucleotides were effective in increasing L-[3H]glutamate binding to the type I preparation. The nucleotide specificity of the glutamate binding enhancement therefore shows a marked similarity with the nucleotide specificity in evoking the synergistic taste effect in humans.

Studies on the binding of adenylyl-3', 5'-cytidine to ribonuclease

The interaction of adenylyl-3',5'-cytidine (ApC) with ribonuclease-A (RNAase-A) was studied by steady-state kinetics and ultraviolet difference spectroscopy. X-ray difference Fourier synthesis at 4 A resolution was also used to study the binding of ApC to RNAase-S. Unlike well-studied compounds like uridylyl-3',5'-adenosine, ApC binds in an unique way: (1) the cytidine moiety is bound to the B1 and R1 sites, (2) the adenosine moiety protrudes to the solution and is not fixed spatially and (3) the phosphate group is bound to the non-specific site (the "Po site") previously postulated (Sawada, F. and Irie, M. (1969) J. Biochem. (Tokyo) 66, 415--418) as the binding site for the 5'-phosphate of uridine 2',5'-diphosphate or uridine 3',5'-diphosphate. This conclusion is consistent with that derived for adenylyl-3',5' -4-thiouridine based on CD difference spectroscopy (White, M.D., Keren-Zur, M. and Lapidot, Y. (1977) Nucleic Acid Res. 4, 843--851). The "Po site" is most likely the epsilon-amino group of Lys 66.

Relationship between polyamine contents and protease activity in the rat submaxillary gland

The effect of polyamines on the protease activity in the submaxillary gland of castrated rats has been investigated in vivo. The protease activity, which is increased by testosterone, is also increased to a lesser degree by the subcutaneous administration of spermidine. The administration of putrescine was less effective than that of spermidine. The increase of polyamine contents in the submaxillary gland of the castrated rats administered either testosterone or spermidine was nearly parallel to the increase of the enzymatic activity. The administration of methylglyoxal bis(guanylhydrazone), a potent inhibitor of spermidine synthesis, with testosterone inhibited slightly the increase of the protease activity by testosterone, while the administration of the inhibitor with spermidine had essentially no effect on the increase of the enzymatic activity by spermidine. The administration of testosteorne also caused a slight increase of S-adenosyl-L-menthionine decarboxylase activity. These results suggest that spermidine synthesis may be necessary for the stimulation by testosterone of protease synthesis in the rat submaxillary gland.

Crystal structure of monoclinic ribonuclease-S at 4 A resolution. The mode of binding of 4-thiouridylic acid and a fragment of folic acid, p-aminobenzoylglutamic acid

A four-A electron density map was calculated for the monoclinic crystal of ribonuclease-S (RNase-S) based on two heavy-atom derivatives. Close geometrical similarity was found between the two crystallographically independent RNase-S molecules (called molecules ZA and ZB) in this crystal and that (called molecule Y) in the trigonal crystal. Using the rotational and translational parameters relating these three molecules, it was established that the crystallographic two-fold symmetry between the two molecules ZA in the monoclinic crystal was exactly identical to that between the two molecules Y in the trigonal crystal, suggesting the tendency of RNase-S molecules to associate in this way although the interaction is weak. The 4-A difference Fourier maps calculated for the monoclinic crystal established the following conclusions. (1) 4-Thiouridine-2'(3')-monophosphates binds to the B1 and R1 sites like other pyrimidine nucleoside-2'(3')-monophosphates as expected from previous spectrophotometric studies, but not to the B2 site even at the concentration of 20 mM. An attempt to visualize the photoproduct generated by irradiation of near-ultraviolet light in this complex failed. (2) p-Aminobenzoylglutamic acid, a fragment of folic acid, seems to bind to RNase-S with its benzene ring close to the B2 site and the alpha-carboxylate group close to the p1 site. The model is compatible with most of the chemical results obtained by Sawada et al. ((1977) Biochim. Biophys. Acta 479, 188-197).