Biomedical subjects
Publications and source records attributed to K Fuji.
New methods for asymmetric reactions developed by the author's group are outlined. They include asymmetric nitroolefination through an addition-elimination process, asymmetric synthesis utilizing 2,2'-disubstituted and 8,8'-disubstituted binaphthyl derivatives, and enantioselective alpha-alkylation of carbonyl compounds under conditions with absolutely no external chiral environmental factors.
Twenty-four previously untreated patients with a diagnosis of prostatic cancer were treated with chlormadinone acetate (CMA) alone (100 mg/day) for 4 weeks, and luteinizing hormone-releasing hormone analogue (LH-RHa) was added for the next 24 weeks. Marked decreases in blood LH, testosterone (T), prostate specific antigen (PSA), gamma-seminoprotein (gamma-Sm), and prostatic acid phosphatase (PAP) were observed after a single dose of CMA. T levels were significantly increased 3 days after the initial dose of LH-RHa, and did not return to the pretreatment level. There were no significant increases in any of the markers, nor were there any flare-up cases. Triglyceride levels, which were slightly elevated before the start of treatment, were significantly decreased 24 weeks after the completion of combined therapy. PSA was evaluated as partial response (PR) or better in 86.7% of the patients. Overall evaluation showed PR or better in 75.0% of the patients. These findings suggest that prior administration of CMA followed by combined administration with LH-RHa is useful in the treatment of prostatic cancer. No negative effects on lipid metabolism were observed at any time during the treatment period.
A gene for prokaryotic pyruvate carboxylase (PC) was cloned from Bacillus stearothermophilus. It has an open reading frame of 3441 base pairs which can code for a protein of 128,353 Da. Not only the molecular size and domain organization but also the deduced amino acid sequence of B. stearothermophilus PC are similar to those of eukaryotic PCs.
The degeneration of cholinergic neurons may be responsible for cognitive impairment in patients with Alzheimer's disease (AD). Since nerve growth factor (NGF) plays an important role in the survival and maintenance of cholinergic neurons in the central nervous system, this factor may have some beneficial effects on the cognitive impairment observed in patients with AD. However, since NGF does not cross the blood-brain barrier and is easily metabolized when administered peripherally, it can only be used when directly injected into the brain. In this review, we show that repeated oral administration of the NGF synthesis stimulators, idebenone and propentofylline, partially restored the age-associated decrease of NGF in the frontal and parietal cortices. Furthermore, this treatment attenuated the impairment of performance in the water maze, passive avoidance, and habituation tasks in rats with bilateral forebrain lesions, and in rats which had received continuous infusion of anti-NGF antibody into the septum. The behavioral improvement induced by idebenone and propentofylline was accompanied by recovery of both the reduced activity of choline acetyltransferase and the changes in [3H]QNB binding. These results suggest that the use of NGF synthesis stimulators may provide a novel therapeutic approach to cholinergic dysfunction.
A monofatty acid ester of glucosamine (PGlcN) was synthesized to provide liposomal membranes with a positive charge, and the trapping efficiency of negatively charged substances (superoxide dismutases, SODs) into cationic liposomes containing PGlcN or stearylamine (SA) prepared by various methods was compared to find the most efficient trapping methods. We demonstrated that cationic liposomes, which were prepared in a buffer of low ionic strength containing sorbitol by a simple hydration method, could entrap a large amount of negatively charged SODs which retained their activity, as compared with cationic liposomes prepared in a buffer of high ionic strength. We also showed a reverse-phase evaporation method entrapped a large amount of SODs. However, SODs were inactivated during the preparation; therefore, this method was not suitable to entrap the enzyme. Freeze-thaw method induced the formation of cationic liposomes which were smaller than extruded liposomes and could entrap the SODs in a buffer of low ionic strength. Dehydration-rehydration method with a buffer of low ionic strength also entrapped a large amount of SODs, indicating that the integrity of liposomes was lost in the lipid bilayer after freeze-drying and the SODs were entrapped in the reconstruction of liposomes during rehydration. These findings showed that the hydration method based on electrostatic attraction with a buffer of low ionic strength was simple and the most effective for entrapping SODs without loss of their activity.
Nerve growth factor (NGF) plays an important role in the survival and maintenance of cholinergic neurons in the central neuronal system. Since this factor does not cross the blood-brain barrier and is easily metabolized by peptidases when administered peripherally, it can be used for medical treatment only when directly injected into the brain. We report here that repeated oral administration of the stimulators for the NGF synthesis, idebenone and propentofylline, produced a significant recovery of the reduced NGF content in the frontal and parietal cortices of aged rats. These compounds also improved deficits of performance in water maze, passive avoidance and habituation tasks in basal-forebrain-lesioned rats. These results suggest that the use of the stimulators for the NGF synthesis may provide a therapeutic approach to cholinergic dysfunction.
The effects of repeated propentofylline administration on impairments of learning and memory in rats with basal forebrain lesions were investigated in several behavioral tasks (water maze, habituation and passive avoidance tasks). Rats were subjected to all the tasks in sequence. Basal forebrain lesions produced by bilateral injections of ibotenic acid (approximately 6 micrograms on each side) severely impaired performance in water maze, habituation and passive avoidance tasks. Repeated administration of propentofylline (10 and 25 mg/kg per day for 14 days, p.o.) improved the deficits of performance in a water maze task, even when administration began one week after the basal forebrain lesions were produced. The impaired performance in habituation and passive avoidance tasks was also markedly ameliorated after repeated administration (24 and 26 days) of propentofylline. The rats with basal forebrain lesions exhibited a significant decrease in choline acetyltransferase activity in the cortex. Propentofylline significantly increased hippocampal choline acetyltransferase activity in basal forebrain-lesioned rats compared with that in vehicle-treated basal forebrain-lesioned rats. However, cortical choline acetyltransferase activity in basal forebrain-lesioned animals was not affected by repeated propentofylline administration. These results indicate that repeated administration of this agent ameliorated the impaired performance of basal forebrain-lesioned rats in part by increasing hippocampal choline acetyltransferase activity. Propentofylline might be useful for the treatment of amnesia and dementia.
Basal forebrain (BF) lesions induced by ibotenic acid produced increases in the Bmax and Kd values of [3H]QNB binding sites in the frontal cortex, parietal cortex, and hippocampus. Twenty-eight-day successive administration of propentofylline (10 and 25 mg/kg, p.o.) significantly reduced the Kd values of [3H]QNB binding sites, to the levels of those in a sham group, in a dose-dependent manner. Moreover, propentofylline (25 mg/kg, p.o.) significantly reduced the Bmax value of [3H]QNB binding sites compared with that in a vehicle-treated BF-lesioned group. These results suggest that successive administration of propentofylline ameliorates changes in muscarinic cholinergic receptors through improving presynaptic cholinergic dysfunction.
Methyl-D-glucosamine-3,6-dilauroyl, dimyristoyl, dipalmitoyl or distearoyl esters were synthesized as positively charged lipids. They were incorporated into phosphatidylcholine liposomal membranes and the entrapment of superoxide dismutase (SOD) into the liposomes was attempted. The efficiency of the SOD-entrapment into the positively charged multilamellar vesicles (MLVs), comprising egg yolk phosphatidylcholine and synthetic glucosamine diesters, was enhanced by the addition of cholesterol to the membranes. A differential scanning calorimetric study showed that the miscibility (solubility) of glucosamine diesters in phosphatidylcholine-bilayers increased on the addition of cholesterol to the membranes. Cholesterol assisted in the mixing of phosphatidylcholines with positively charged glucosamine diesters and increased the positive charges on the liposomal membranes. This was confirmed by incremental increases in the zeta-potential of liposomal membranes with an increase in the cholesterol content. Entrapment of SOD thus became more efficient due to the enhanced electrostatic attraction between the positively charged membranes and the negatively charged SOD, and/or the electrostatic repulsive interactions between positively charged membranes; the latter interactions induced a thickening of the water layer in MLVs.
The effects of naftidrofuryl oxalate (LS-121) on 5-HT2 receptors in the brain were assessed in mice on the basis of quantitative autoradiography and head-twitch responses. LS-121 inhibited [3H]ketanserin (2 nM) binding in all brain areas assayed in which there were 5-HT2 receptors, such as the frontal cortex, cingulate cortex, parietal cortex, occipital cortex, temporal cortex, nucleus accumbens, caudate-putamen, olfactory tubercle and hippocampus. In the frontal cortex, which has the highest density of 5-HT2 receptors, the Ki value of LS-121 was 6.08 x 10(-8) M. The inhibitory potencies of methysergide and ritanserin for 5-HT2 receptors were about 16- and 60-fold stronger, respectively, than that of LS-121. Moreover, in behavioral studies, LS-121 (12.5-50 mg/kg i.p.) produced dose-dependent and significant inhibitory effects on head twitches induced by 5-hydroxytryptophan (5-HTP) plus pargyline, which is a 5-HT2 receptor-dependent behavior in mice. These results suggest that LS-121 inhibits 5-HTP plus pargyline-induced head twitches by blocking 5-HT2 receptors.
Recordings of noxious intra-arterial bradykinin (BK)-induced chemonociceptive and spontaneous activity from 30 single spinal lamina V neurones of the dorsal horns in non-anaesthetized and decerebrated rabbits, were performed with tungsten microelectrodes. Intravenous injection of midazolam (0.2 mg/kg; 7 neurones) depressed BK-induced neural discharges by 55.0 +/- 6.2% (P less than 0.05) and 57.9 +/- 8.4% (P less than 0.05) 5 and 25 min after administration, respectively. Treatment with flumazenil (0.2 mg/kg, i.v.; 7 neurones), administered 20 min after midazolam, completely reversed the inhibition by midazolam of the BK-induced spinal lamina V neural responses and spontaneous neuronal activity. In contrast, a large dose of naloxone (1.0 mg/kg, i.v.; 6 neurones), administered 20 min after midazolam, failed to alter the midazolam-induced depressant effects on the nociceptive responses, at the spinal dorsal horn. Treatments with flumazenil (5 neurones) and naloxone (5 neurones) did not influence either the spontaneous or the BK-induced neuronal discharges, recorded in spinal lamina V cells. Midazolam depressed the nociceptive responses probably through its agonistic activity on the binding to the GABA-benzodiazepine-barbiturate system in the spinal dorsal horn.
The DNA cleavage reaction by viologen and related compound such as 2,7-diazapyrenium salt was investigated. These viologen analogues were successfully incorporated into the oligothymidylate in the form of covalent bonding at the site of the phosphorous backbone through the linker arm.
We have investigated whether administration of staurosporine, which has been reported to induce differentiation in the human neuroblastoma cell in vitro, attenuates amnesia induced by basal forebrain lesion in rats. Multiple dosage of staurosporine at the doses of 0.05 and 0.1 mg/kg (i.p.) attenuated the impaired performance of the water maze task. Moreover, staurosporine (0.1 mg/kg) reversed the decrease of choline acetyltransferase activity in the fronto-parietal cortex. These results suggest that staurosporine attenuates amnesia through reversal of deficits in cholinergic neurons induced by basal forebrain lesion, and that neurotrophic factor-like substances may open the way for novel therapeutic approaches to Alzheimer's disease.
In a water maze task, the goal latency and distance of swimming onto the platform of aged rats (24 months old) were slowly shortened by repeated training compared with those of young rats (8 weeks old). A significant decrease in choline acetyltransferase activity in the frontal cortex, parietal cortex and striatum was observed in aged rats. Moreover, the number of neuronal cells in the hippocampal CA1 subfield and dentate gyrus of aged rats was smaller than that of young rats. The atrophy of striatal cells was observed. These results suggest that age-related delay of acquisition is due to the above-mentioned biochemical and histological changes, and that rates of aging in biochemical and morphological parameters are different in the discrete brain areas.
Two active sites responsible for antitumor activity, an oxirane ring and an alpha-methylene-cyclopentanone moiety, have been extracted from studies on the structure-activity relationship of the cytotoxic diterpenoids isolated from Rabdosia shikokiana. Series of the simplified cyclopentanone derivatives containing both of the two active sites in the molecule have been synthesized and evaluated for cytotoxicity against P 388 cells. The compounds possessing both of two active sites displayed cytotoxicity at a concentration of 1 microgram/ml, while those possessing a single active site showed no activity.
Several viologen-tagged oligodeoxynucleotides in the form of covalent linkage at the specific site of the phosphorous backbone were synthesized and characterized. Incorporation of viologen molecules was confirmed by the 31P-NMR, 20% PAGE analysis, enzymatic degradation, and uv, ESR spectra of the derived cation radical. The Tm values and CD spectra of the modified strands with their complementary strands indicate that the introduction of the viologen molecule via linker arm causes no significant perturbation in duplex structure.
We report here that the specific Fab' fragment of anti-nerve growth factor (NGF)-antibody (anti-NGF, 12, 120 and 400 micrograms/4 weeks, i.c.v.) impairs learning and memory. The goal latency of the control rats in water maze task was rapidly shortened by training compared to those of the anti-NGF-treated rats. The degree of reduction in movement counts of the anti-NGF-treated rats in habituation task was significantly smaller than that of the control rats. However, the step-through latency of the anti-NGF-treated rats was not significantly shorter than that of the control rats. With regard to the choline acetyltransferase activity, no effects were observed in any of the brain regions. Anti-NGF treatment altered nuclear morphology in the hippocampus and parietal cortex. As a result, it seems that the anti-NGF-induced amnesia could be due to an impairment of nuclear morphology.
Alzheimer's disease is characterized by the loss of cholinergic neurons in the nucleus basalis of Meynert and by a primary loss of memory function. Since staurosporine has been reported to induce differentiation in human neuroblastoma cells in vitro, we studied the effects of staurosporine on the amnesia induced by basal forebrain-lesion in rats. Staurosporine (0.05 and 0.1 mg/kg intraperitoneal) attenuated the impaired performance of water maze and passive avoidance tasks, even though the drug administration began 2 weeks after the lesion. Moreover, staurosporine (0.1 mg/kg) partially reversed the decrease of choline acetyltransferase activity in the fronto-parietal cortex induced by basal forebrain-lesion. These results suggest that staurosporine attenuates impairment of learning through reversal of damage to cholinergic neurons induced by basal forebrain-lesion. This evidence indicates that neurotrophic factor-like substances may be used in novel therapeutic approaches to Alzheimer's disease.