Acid-stable fluorescent advanced glycation end products: vesperlysines A, B, and C are formed as crosslinked products in the Maillard reaction between lysine or proteins with glucose.

Vesperlysines A and B, 6-hydroxy-1,4-di{6-(L-norleucyl)}-1H-pyrrolo[3,2-b]pyridinium and its 5-methyl derivative, respectively, and Vesperlysine C, 5-hydroxy-methyl-1,6-di{6-(L-norleucyl)}-1H-pyrrolo[3,4-b] pyridinium, are isolated as major fluorescent advanced glycation end products (AGEs) from hydrochloric acid hydrolysis of AGE-BSA, bovine serum albumin (BSA) modified by the Maillard reaction with glucose. These fluorophores are glycation products and not artifacts of hydrolysis, since they are also detected in the reaction mixture of lysine and glucose prior to hydrolysis. Vesperlysines are crosslinked products from two lysine side-chains in proteins and are considered to be generated from lysines and the oxidative degradation of glucose, because the six carbon skeleton of glucose in its original form was not incorporated into each structure.

Highly selective aldose reductase inhibitors. 3. Structural diversity of 3-(arylmethyl)-2,4,5-trioxoimidazolidine-1-acetic acids.

Accumulation of intracellular sorbitol, the reduced product of glucose, catalyzed by aldose reductase (AR) (EC 1.1.1.

Highly selective aldose reductase inhibitors. II. Optimization of the aryl part of 3-(arylmethyl)-2,4,5-trioxoimidazolidine-1-acetic acids.

Accumulation of intracellular sorbitol, the product of glucose reduction catalyzed by aldose reductase (AR) [EC 1.1.1.

aFGF, endogenous satiety substance, facilitates learning, memory and immune function in aging.

aFGF injection s.c. once a week into SAMP8 was begun at 3 weeks after birth and continued for 10 months.

Protection against impairment of memory and immunoreactivity in senescence-accelerated mice by acidic fibroblast growth factor.

Subcutaneous injection of aFGF once a week into senescence-accelerated mice (SAM)P8 was begun at 3 weeks after birth and continued for 10 months. Saline was injected as a control. Learning and memory and cellular immunological functions in the aFGF group were enhanced significantly, while those of the saline group deteriorated.

Highly selective aldose reductase inhibitors. 1. 3-(Arylalkyl)-2,4,5-trioxoimidazolidine-1-acetic acids.

A series of 3-(arylalkyl)-2,4,5-trioxoimidazolidine-1-acetic acids (1) was prepared and tested for aldose reductase (AR) and aldehyde reductase (ALR) inhibitory activities. These compounds showed strong inhibitory activity against AR without significant inhibitory activity for ALR. The ratio of IC50(ALR)/IC50(AR) was > 1000 in some compounds.

Crosslines, fluorophores in the AGE-related cross-linked proteins.

We can summarize our results as follows: (1) A pair of fluorescent crosslines were isolated from the Maillard reaction mixture; (2) AGE-proteins contained crossline-like structures, and (3) crossline-like immunoreactivities were accumulated in renal tissues of diabetic rats. From these results we concluded that fluorophores in AGE proteins have crossline-like structures and we had the first indication that XLs could be markers for renal disorders.

Memory facilitation educed by food intake.

Acidic fibroblast growth factor (aFGF) in rat CSF increased 1000 times in the 2-h period after food intake, or IP, or ICV glucose infusion. The ICV application of aFGF dose dependently depresses and anti-aFGF antibody facilitates food intake. aFGF is produced in the ependymal cells and released into the CSF in response to increased glucose in the CSF caused by food intake.

3 beta-Hydroxysialic acid glycosides. I. Calcium-binding ability and chemical and enzymatic stabilities.

Methyl alpha- and beta-glycosides of N-acetylneuraminic acid (Neu5Ac) and N-acetyl-3 beta-hydroxyneuraminic acid (Neu5Ac beta 3OH) (1-4) were prepared to evaluate their calcium-binding ability. (Methyl alpha-glucopyranosidonyl) alpha- and beta-, and 4-methylumbelliferyl alpha-glycosides of Neu5Ac and Neu5Ac beta 3OH (5-10) were also synthesized for the comparison of chemical and enzymatic stabilities, respectively. Methyl beta-glycosides of Neu5Ac and Neu5Ac beta 3OH, 3 and 4, respectively, showed intense calcium-binding abilities, while no such ability was observed in the corresponding alpha-glycosides, 1 and 2.

Relationship between density of muscarinic receptors and nasal hypersecretion in a nasal allergic model.

In guinea pigs actively sensitized with ovalbumin, we have observed that nasal hyperreactivity and hypersensitivity to methacholine causes nasal secretion accompanied by an increase in the density of muscarinic acetylcholine receptor (m-ACh.R) following the appearance of nasal symptoms induced by the ovalbumin challenge. Therefore in the present investigation, we studied the relationship between the density of m-ACh.

Regulatory effect of neurotropin on nasal mucosal hypersensitivity in guinea pigs caused by SART (intermittent exposure to cold) stress.

We stated that SART-stressed guinea pigs showing nasal mucosal hypersensitivity would serve as an animal model for the in vivo evaluation of antiallergic drugs. In the present study, the mode of action of Neurotropin on nasal allergy compared with those of antiallergic drugs was studied by using SART-stressed guinea pigs. Daily administrations of Neurotropin improved the methacholine-induced hypersecretion and histamine-evoked sneeze response, which are parameters of nasal mucosal hypersensitivity, and increased the density of muscarinic ACh receptors located on the nasal mucosa caused by SART stress.

Pathophysiological significance of brain acidic fibroblast growth factor.

The acidic fibroblast growth factor (aFGF) in rat cerebrospinal fluid (CSF) increased 1000 times in the 2 hr period after food intake, or intraperitoneal (IP) or intracerebroventricular (ICV) glucose infusion. It diffused into the brain parenchyma and was taken up into neurons in the hypothalamus, hippocampus, etc..

First isolation of gamma-L-glutamyl-gamma-aminobutyric acid from bovine brains.

We had obtained some immunohistochemical indications which suggested that peptide(s) containing GABA at the C-terminal could exist in specific neurons in brains. We therefore sought such GABA conjugate(s) by isolating an acidic GABA-dipeptide from bovine brains and determined its structure as gamma-L-glutamyl-gamma-aminobutyric acid (gamma-L-Glu-gamma Abu:GluGABA). Its gamma-linkage was determined by a mass-spectrometric (B/E linked scan SIMS) analysis; its chirality was established by a chiral column HPLC technique.

Changes in muscarinic acetylcholine receptors in the isolated duodenum from repeatedly cold-stressed rats and the effect of neurotropin.

In rats repeatedly cold-stressed by specific alternation of rhythm in environmental temperature (SART-stressed rats), the contractile response to acetylcholine (ACh) of the isolated duodenum was remarkably decreased, whereas the contractile responses to K+, Ba2+ and Ca2+ were comparable to those in non-stressed rats. The amount of [3H]quinuclidinyl benzilate in the duodenum of SART-stressed rats was about 50% of that in non-stressed rats, but the KD value remained unchanged. Long-term administration of hexamethonium prevented the changes in SART-stressed rats.

Mechanism of nasal secretion mediated via nerve reflex in guinea pigs and evaluation of antiallergic drugs.

In order to confirm the mechanism of nasal secretion mediated via a nerve reflex in guinea pigs, the secretory response from the contralateral side was studied which was induced by local application of various stimulators. There was no difference in the nasal secretion between the contralateral and the stimulated sides when the secretion was induced by allergen, histamine, and capsaicin at lower doses. Methacholine caused a nasal secretion only on the stimulated side.

Mechanism of hyperalgesia in SART stressed (repeated cold stress) mice: antinociceptive effect of neurotropin.

Exposing mice to 24 and 4 degrees C in alternate 1 hr periods in the day time and maintaining 4 degrees C at night for several days decreases the tail clamp pressure required to evoke pain behavior. This model is referred to as SART (specific alternation rhythm of temperature) stress. An extract from inflamed skin of rabbits inoculated with vaccinia virus (neurotropin) clearly normalized the hyperalgesia in this SART stress model.

A new method of the measurement of nasal secretion in guinea pigs.

A simple quantitative method to measure nasal secretion in guinea pigs is described. Nasal secretion was measured with a piece of cotton thread dyed with fluorescein at one end which was inserted into an anterior naris and kept there for 60 s. The stretch of color of a thread dyed with fluorescein was proportional to fluid volume and to increase in weight of a thread due to absorbed nasal secretion induced by nasal provocation.

Nasal mucosal hypersensitivity in guinea pigs intermittently exposed to cold.

To develop an animal model for experimental nasal hypersensitivity and hyperreactivity, guinea pigs were subjected to intermittent exposure to cold temperature (intermittent cold stress, SART stress) for 5 consecutive days. In SART-stressed guinea pigs, nasal mucosal hypersensitivity to histamine evoking sneeze response and nasal hypersecretion in response to methacholine were observed. The hypersensitivity remained for further 7 days after being released from SART stress.

Production of methylguanidine from creatinine via creatol by active oxygen species: analyses of the catabolism in vitro.

The chemical oxidative conversion of creatinine (Cr) into methylguanidine (MG) has been followed by 1H-NMR and HPLC. By using active oxygen species generated by Fenton's reagent (Fe2+ and H2O2) or the similar reagent (Fe3+ and H2O2), creatol (CTL), a metabolite newly isolated from the urine of uremic patients, and creatones A and B were experimentally detected in the reaction mixture and implicated as successive intermediates in the pathway from CR to MG. An alternative oxidation of Cr to demethylcreatinine (glycocyamidine) was also observed.

[Effect of neurotropin on experimental osteoarthritis].

The effect of Neurotropin on osteoarthritis was investigated in comparison with those of prednisolone and indomethacin. 1) There were remarkable decreases in the staining intensity to safranin-O and in the contents of uronic acid, total hexosamine and hexose in the articular cartilage of rabbits in which experimental osteoarthritis was induced by the injection of papain into the knee joint. In the Neurotropin-treated group, the decrease in the staining intensity to safranin-O and the contents of uronic acid, total hexosamine and hexose were evidently recovered.

Isolation of glutamyltaurine from bovine brains and proof of its gamma-linkage by the B/E linked scan SIMS technique.

We isolated a glutamyltaurine from bovine brains and determined its structure as gamma-glutamyltaurine (gamma-Glu-Tau; glutaurine) by use of a new mass spectrometric technique [B/E linked scan sputtered ion mass spectrometry (SIMS)], which we have recently shown to be useful for distinguishing the gamma- from the alpha-isomer of glutamyl-dipeptides. Neither the alpha-isomer of glutamyltaurine nor any aspartyltaurines could be detected in bovine brain.

Strain differences in guinea pigs' bronchial sensitivity to acetylcholine.

The bronchial sensitivity to acetylcholine (ACh) of guinea pigs of various strains was investigated to clarify strain differences. Inbred Strain 2, Strain 13 and JY-1 and non-inbred Hartley strain (two colonies) were used in this experiment. (1) Guinea pigs were exposed to 0.