Reversal by 3,3?,5-triido-l-thyronine of the working memory deficit, and the decrease in acetylcholine, glutamate and ?-aminobutyric acid induced by ethylcholine aziridinium ion in mice

The effect of 3,3',5-triiodo-L-thyronine (T3) on working memory in ethylcholine aziridinium ion (AF64A)-treated mice was studied in a delayed non-matching to sample task using a T-maze. After behavioural testing was completed, mice were killed by microwave irradiation and regional brain levels of acetylcholine, aspartate, glutamate, glutamine, glycine, taurine, and gamma-aminobutyric acid (GABA) were measured by high-performance liquid chromatography with electrochemical detection. Treatment with AF64A (7 nmol, i.c.v.) produced a deficit in working memory performance in the non-matching to sample task at 30 s delay, and decreased acetylcholine, glutamate, and GABA levels in the hippocampus, but not in the septum and cerebral cortex. Administration of T3 (0.3 mg/kg, p.o., once daily for 6 days) to AF64A-treated animals improved the deficit in working memory performance and reversed the decrease in acetylcholine, glutamate, and GABA levels in the hippocampus. These results indicate that the deficit in performance induced by AF64A can be improved by T3 administration.

A simple T-maze method for estimating working memory in mice. Effect of ethylcholine mustard aziridinium ion (AF64A)

Mice were housed in a cage containing a T maze. A watering place was located at the entrance of the maze. The right and left arms of the maze each had two exits, one of which led to the home cage where food was placed, while the other led to the watering place via a bypass. The exit leading to the home cage in either the right or left arm was alternately closed every 90 min. One-way swinging doors were inserted at the entrance to each arm and between each bypass and the watering place. The mice were given a cholinergic neurotoxin--ethylcholine mustard aziridinium ion (AF64A)--(8 nmol) or saline as a control into the left ventricle 2 weeks before they were housed in the apparatus. Those mice housed in this apparatus mastered the alternation task at a 5-sec delay on day 3 in the sham group and on day 4 in the AF64A group. When a longer delay (5-90 sec) was introduced for the mice that mastered the alternation task at 5-sec delay, the AF64A group made significantly more errors than did the sham group at 60- and 90-sec delays. These results show that the apparatus is useful in estimating working memory in mice with little effort.

A rapid assay for neurotransmitter amino acids, aspartate, glutamate, glycine, taurine and ?-aminobutyric acid in the brain by high-performance liquid chromatography with electrochemical detection

For simultaneous assay of the five neurotransmitter amino acids, Asp, Glu, Gly, Tau, and GABA in brain tissues, a very rapid and simple chromatographic method using high-performance liquid chromatography with electrochemical detection in combination with o-phthalaldehyde derivatization is described. Because the present method permits the determination of these five amino acids within less than five minutes in one chromatographic run, up to 100 samples a working day can be analyzed using an autosampler. Within-run coefficients of variation for these five amino acids were less than 2% (n = 20). The quantitative detection limit was 2.5 pmol for the 5 amino acids. The present method has been applied to the measurement of the five amino acid neurotransmitter levels in several discrete brain regions of mice treated with and without electroconvulsive shock.

Rapid and simultaneous assay of monoamine neurotransmitters and their metabolites in discrete brain areas of mice by HPLC with Coulometric detection

For simultaneous assay of the three monoamine neurotransmitters, norepinephrine, dopamine, and serotonin, and four respective metabolites in brain tissue, a rapid and simple method using high-performance liquid chromatography with coulometric detection is described. Because the present method permits the determination of these target substrates within 10 min or less in one chromatographic run, 150 samples can be analyzed using an autosampler and an integrator in a 24-h period. Within-run coefficients of variation for the target substrates in the standard solution and the whole brain sample were less than 3% and 2% (n = 40), respectively. The quantitative detection limits were 0.01-0.1 pmol. The present procedure was applied to measure the target substrates in several discrete brain areas in mice.

Effects of nefiracetam, a novel pyrrolidone derivative, on brain monoamine metabolisms in mice

The effects of acute and chronic administration of nefiracetam, a pyrrolidone derivative, on monoaminergic neurotransmitter systems in the mouse hippocampus, frontal cortex, hypothalamus, and striatum were studied. The levels of monoamines and of their metabolites were measured by high performance liquid chromatography with electrochemical detection on the first, 7th, and 14th days after nefiracetam was given. The neurochemical effects of nefiracetam were compared with those of oxiracetam and indeloxazine. Acute administration of nefiracetam (10 mg/kg, po) and oxiracetam (10 mg/kg, po) had no effect on the levels of noradrenaline (NA), dopamine (DA), or 5-hydroxytryptamine (5-HT), or on the levels of their metabolites, 3-methoxy-4-hydroxyphenylglycol (MHPG), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), and 5-hydroxyindoleacetic acid (5-HIAA), in any of the regions examined. In contrast, a single dose of indeloxazine (10 mg/kg, po) decreased the levels of MHPG, DOPAC, and 5-HIAA in all regions examined. After chronic administration of nefiracetam (10 mg/kg, po, once daily), the levels of MHPG, DOPAC, and 5-HIAA were higher than control in all regions on the 14th day only. Oxiracetam (10 mg/kg, po, once daily) similarly increased the levels of MHPG, DOPAC, and 5-HIAA in the hippocampus, frontal cortex, and striatum, but not in the hypothalamus. Conversely, indeloxazine (10 mg/kg, po, once daily) decreased the levels of MHPG and 5-HIAA in all regions and the levels of DOPAC and HVA in the hippocampus and striatum as measured on the 7th and 14th days. These results show that nefiracetam has a delayed effect on brain monoaminergic metabolism, and that its effects are similar to those of oxiracetam, but clearly different from those of indeloxazine.

Mice housed in a cage with a maze learn the maze without explicit training

Mice were housed in a cage with a maze. A water tap was placed at the entrance of the maze. The exit of the maze connected with another cage (home cage). Food was placed in the home cage. Three different multiple mazes (types 1-3) were placed. 1) Mice were housed for 10 h a day in the apparatus and then removed to a normal cage for fasting. One trial per day was carried out after fasting for 13 h. In each trial, a mouse was put at the entrance of the maze and then the number of errors and the time till it reached the home cage was counted. Mice reached a learning criterion at Trial 2. 2) Administering scopolamine (0.125-0.5 mg/kg) 30 min before Trial four disturbed the maze work dose dependently in a type 3 maze, the most complex maze among the three, but did not in type 1 and 2 mazes. 3) Administering scopolamine (0.25-1.0 mg/kg) 30 min before Trial 11 to the mouse of the type 3 maze did not disturb the maze work. These results show that a mouse housed in a cage with a maze learns the maze without explicit training and scopolamine can differentially effect performance based upon the degree of training.

[A simple multiple maze test to estimate learning and memory in mice: application to the effect of scopolamine on learning and memory]

The apparatus consists of a home cage, a maze cage and a starting box. A maze with four right-middle-left decisions was placed in the maze cage. The starting box was attached and a water tap was placed at an area corresponding to the entrance of the maze. The exit of the maze and the home cage are connected with a tunnel. Food was placed in the home cage. 1) Mice were housed for 10 hr a day in the apparatus and then removed to another cage for fasting. One trial a day was carried out after fasting for more than 12 hr. In each trial, a mouse was put at the starting box, and then the number of errors (entering a blind alley) and the time until the mouse reached the home cage were counted. The mouse passed through the maze with a small number of errors and time. 2) Administration of scopolamine (0.125-0.5 mg/kg, i.p.) to a mouse that had mastered the maze transiently disturbed the maze performance dose-dependently. 3) Mice were housed for 4 hr a day. Scopolamine (0.25 mg/kg, i.p.) was administered either before or after the housing. Scopolamine disturbed the maze performance in the case of both procedures. These results suggest that the method is useful for estimating the memory in mice.

The enhancement of the hypomotility induced by small doses of haloperidol in the phase of dopaminergic supersensitivity in mice

Dopaminergic supersensitivity in mice was induced by pretreatment with a single injection of haloperidol (4.8 mg/kg). After the pretreatment, further treatment with haloperidol (0.6 or 0.01 mg/kg) was made at varying intervals, and catalepsy, locomotor activity and homovanillic acid (HVA) were measured. The intensity of the supersensitivity was evaluated by enhanced apomorphine (1 mg/kg)-induced climbing behavior. Supersensitivity was displayed on the 2nd and the 4th day. The cataleptogenic effect of haloperidol (0.6 mg/kg) was significantly weakened on the 1st, 2nd and 4th days. The motor inhibitory effect of haloperidol (0.01 mg/kg) increased on the 1st, 2nd and 4th days. Homovanillic acid was measured in the striatum and the prefrontal cortex on the 2nd day. Haloperidol (0.6 mg/kg) increased the concentrations of HVA in both regions of the brain. The increase in the concentrations of HVA in the striatum was blunted after the pretreatment, but such tolerance did not develop in the prefrontal cortex. Haloperidol (0.01 mg/kg) did not influence the concentration of HVA in both regions. These results suggest that the behavioral effect of a small dose of haloperidol may be enhanced, rather than reduced, in the phase of supersensitivity.

The effect of arsenic trioxide on brain monoamine metabolism and locomotor activity of mice

The arsenic trioxide (AsT) content, and monoamine levels in the cerebral cortex, hippocampus, hypothalamus and corpus striatum were determined in mice administered AsT (3 and 10 mg/kg) for 14 days. The vertical and horizontal motor activity was also examined. The AsT content in discrete brain areas differed but was clearly dose-dependent. Metabolites of norepinephrine and dopamine increased in the cerebral cortex, hippocampus and hypothalamus and decreased in the corpus striatum in AsT-treated mice. Metabolites of 5-hydroxytryptamine increased in all the discrete brain areas. The vertical and horizontal motor activity was increased by AsT at 3 mg/kg and decreased by AsT at 10 mg/kg. These results show that AsT modifies CNS metabolism and function at low doses. AsT penetrates the blood-brain barrier to cause these effects.

[A study of the relationship between hearing-aid usage and residual hearing]

Fifty-eight children (from 4 to 19 years of age) with bilateral, symmetrical, sensorineural hearing loss, who had used a hearing aid in only one ear for 1 to 19 years were investigated to study the influence of hearing-aid upon the residual hearing between the used and no used ears. The results were as follows, 1) The average hearing level for the used ear at seven frequencies was 49. 5 dB of pre-hearing-aid usage and was 53. 8 dB of post-hearing-aid usage. The discrepancy of audiograms between the aided and unaided ear was not remarkable. 2) The hearings for both the aided and the unaided ears in Audiograms was progressive for a long time. But no significance relation was observed between changes in used-ear hearing of the aided and unaided ears. 3) When the hearing levels of the children were scrutinised on an individual basis, it was found that 9 cases (15.5%) in both ears, 2 cases (3.4%) in only used ear and 1 case (1.7%) in only no used ear out of 58 cases showed deterioration of hearing. 4) These data did not lead us to the conclusion that hearing-aid usage was detrimental on the residual hearing of children with sensorineural hearing loss.

A case of nephrotic syndrome due to alpha-mercaptopropionyl glycine in a patient with familial cystinuria

A 26-year-old male with nephrotic syndrome (NS) due to alpha-mercaptopropionyl glycine (MPG) is described. In March, 1988, he was diagnosed as having familial cystinuria after receiving urolithiasis treatment since December, 1985. Massive proteinuria and slight pedal edema were noted. Nephrotic syndrome was suggested and renal biopsy was performed. The renal pathological finding demonstrated membranous glomerulonephritis (MN) at stage I. This case was defined as NS clinically associated with MPG, and glucocorticoid intake was initiated. The response to the glucocorticoids was fairly good with no clinical problems after discontinuation of MPG, and the cystinuria was maintained with alkaline medication. The patient's parents and younger brother were suggested and confirmed to have cystinuria based on urinary aminogram analysis, but displayed no symptoms. We present a rare case of NS due to MPG therapy in a patient with familial cystinuria. However, the mechanism of onset remains unclear.

[Some aspects of third molars with regard to the development of malocclusions]

Although the orthodontist is constantly aware of the developing third molar and its possible effects on the dentition during and after orthodontic treatment, the relationship between the third molar and the development of malocclusion had not been resolved. To attempt to clarify some of the problems associated with the third molar, an analysis of the factor in fluencing on the dentition and denture frame was performed. In this study, twenty-one adult cases which had no prothodontic correction of the tooth shape and orthodontic treatment with at least three wisdom teeth were used for evaluation of the denture frame structure and occlusion. The case which impacted third molar (M3 impacted group) showed less than 25 degree mandibular plane angle (FH-MP) without exception, while the case which the third molar erupted (M3 erupted group) were able to divide into high angle (more than 30 degree of FH-MP) and low angle (less than 29 degree of FH-MP) groups. The M3 impacted with low angle group and M3 erupted with low angle group showed relatively normal occlusion and favorable denture frame structure, but M3 erupted with high angle group indicated that the denture frame composition was affected by posterior discrepancy especially the steepness of occlusal plane which might be the over eruption of posterior teeth. The M3 erupted with high angle group also included two cases of severe anterior open-bite with skeletal deformity. These findings suggest that the posterior discrepancy due to existence of third molars influence on the dento-facial-skeletal structure and development of malocclusions.

Very rapid and simple assay of taurine in the brain within two minutes by high-performance liquid chromatography with electrochemical detection

We describe a very rapid and simple method for the assay of taurine (Tau) in the brain tissue, using high-performance liquid chromatography (HPLC) with electrochemical detection in combination with precolumn o-phthalaldehyde (OPA) derivatization. The present method permits Tau assay within 2 min in one chromatographic run. Recovery for Tau was 107.4 +/- 1.3% (SD, n = 10). Within-run coefficients of variation were +/- 1.6% (n = 15). The limit of quantitative detection of the method was 0.1 pmol for Tau. The present method has been applied to the measurement of Tau levels in several discrete brain areas of the mouse.

[Measurement of the abrasion of radioactive teeth by dentifrices]

The purpose of this study is to assess the dentifrice abrasivity of both commercially available products and test products. The assessment of abrasivity was carried out by the measurement of 32P released from tooth by using radioactive dentifrice abrasion (RDA) method. In dentine, RDA values, which show the polishing ability for dentine, were 65-100 with dentifrices with normal cleaning power and 106-182 with those with high cleaning power, respectively. On the other hand, REA values which show the polishing ability for enamel were 12-405 with both market products and test products. The difference of the REA values according to the dentifrices appears to be largely influenced by the difference of polishing agents of each dentifrice. It is concluded that RDA method is usefull for assessing of dentifrice abrasivity. However, particular attention should be given to the abrasion of dentine.

Effects of 24-hr fasting on methamphetamine- and apomorphine-induced locomotor activities, and on monoamine metabolism in mouse corpus striatum and nucleus accumbens

The effects of 24-hr fasting on the vertical (VMA) and horizontal (HMA) locomotor activities, on cage climbing activity and on brain monoamine-related substances, were examined using male ddY mice. Both the VMA and HMA increased with fasting, but not the cage climbing activity. Methamphetamine (2 mg/kg, SC) increased the VMA and HMA in both the feeding and fasting mice, whereas with apomorphine (0.1 mg/kg, SC) both decreased. Furthermore, pretreatment with haloperidol (0.025 mg/kg, SC) showed no influence on the methamphetamine-induced VMA increase in both the feeding and fasting mice. However, pretreatment with haloperidol inhibited the methamphetamine-induced HMA increase in both the feeding and fasting mice and showed a higher level of HMA in fasting mice than in feeding mice. When measuring brain monoamine-related substances, the DA, NE, 5-HT, and 5-HIAA levels in the corpus striatum increased, whereas the 3-MT levels decreased. The monoamine levels in the nucleus accumbens of fasting mice were the same as those in feeding mice, except for a decrease of the 3-MT level. These results suggest that the locomotor activity in fasting mice may be increased by a change in the sensitivity of dopaminergic neurons in the corpus striatum.

[Clinical effects of chewing gum containing egg-white lysozyme and mace extract]

The purpose of this study was to evaluate the clinical effect of mace extract and egg-white lysozyme in two brands of chewing gum on gingival condition. Ever since mace extract containing dihydroguaiaretic acid was reported to inhibit the growth of Streptococcus mutans, plans were devised to include it in commercially available chewing gum. Before starting this study, two different types of experimental chewing gum containing mace extract or egg-white lysozyme were made up. A control was also prepared containing neither agent. The periodontal condition of 68 patients with gingivitis was determined based on PMA index (PMA), gingival index (GI), gingival bleeding index (GBI) and plaque scoring system (PSS) and randomly classified into three groups. Each group was instructed to use one or the other of the above type chewing gums after every meal. The results were as follows: 1. No clinical changes were observed in the control group during this study. 2. Gingival inflammation (PMA, GI, GBI) significantly improved as a result of using the experimental gums. 3. Plaque reduction was found only in the mece-extract gum group. 4. No clinical side effects were detected during this study.

Simple determination of acetylcholine and choline within 4 min by HPLC-ECD and immobilized enzyme column in mice brain areas

A rapid and simple method using a combination of high-performance liquid chromatography (HPLC) with electrochemical detection (ECD) and an immobilized enzyme column herein is described for simultaneous assay of acetylcholine (ACh) and choline (Ch) in discrete brain areas of the mouse. Perchloric acid extracts of small brain tissues were injected directly onto the HPLC system with no pre-cleanup procedure. The ACh and Ch levels were determined within 4 min for each chromatographic run. Recoveries were 100.0 +/- 4.8% for ACh and 96.1 +/- 1.4% (mean +/- S.D., n = 10) for Ch. Detection limits for both compounds were 0.25 pmol (signal-to-noise ratio of three). The present method has been applied to the measurement of Ch and ACh in several discrete brain areas of the mouse.

Nasal mucociliary clearance in Sjögren's syndrome. Dissociation in flow between sol and gel layers

Nasal mucociliary clearance was measured with two methods in 8 patients with Sjögren's syndrome and in 6 normal subjects. The movement of two different tracers placed 1.5 cm posterior to the inferior turbinate tip was measured respectively. The transport rate of a 500 microns anion resin particle tagged with 99mTc was measured. The clearance of 10 microliters saline labelled with 99mTc was monitored and the clearance rate was calculated. Whereas the measurement with the particle method revealed the lowered transport rate in Sjögren's syndrome, measurement with the saline method did not reveal any difference in clearance rate between the two groups. Since the former method measures the transport of particle in the gel phase (the outer mucous layer) and the latter measures the clearance of both gel and sol (periciliary fluid) layers, it is postulated that there is a dissociation of flow between sol and gel layers in Sjögren's syndrome.

[In vivo study of bacterial invasion in root planed and citric acid treated radicular surfaces of periodontally involved human teeth]

The purpose of this study was to investigate whether plaque bacteria invade the exposed radicular dentin after root planing or chemical root treatment in vivo. Eighteen caries-free human periodontally involved teeth with hopeless prognoses were studied. Fourteen teeth were scaled and root planed with hand curette type scalers. The proximal surface of each treated tooth was designated as the RP surface. The remaining half of the proximal surface was treated with citric acid (pH 1.0) for 3 minutes and was designated as the CA surface. Four untreated teeth served as controls. After 4 weeks, the teeth were extracted, and were processed for light microscopy and for scanning electron microscopy concerning bacterial invasion into the supragingival radicular dentin. The following results were obtained. 1. Radicular cementum was present on most untreated tooth surfaces. However, bacteria were never seen in the dentinal tubules. 2. Bacterial invasion into the dentinal tubules was observed in five of the 10 proximal surfaces (50% of the RP surfaces) and in nine of the 10 proximal surfaces (90% of the CA surfaces). 3. The depth (9.5 +/- 24.1 microns vs 84.6 +/- 136.3 microns) and percentage (0.8 +/- 2.1% vs 20.3 +/- 17.3%) of bacterial invasion in the dentinal tubules of the RP surfaces was lower than that of the CA surfaces. 4. Cocci and short rods were present in the supragingival dentinal tubules. 5. Since CA surfaces may accelerate bacterial invasion the citric acid treatment might be harmful in patients with inadequate plaque control.

Very rapid assay of gamma-aminobutyric acid in mouse brain regions within 3 minutes by high-performance liquid chromatography with electrochemical detection

For assay of gamma-aminobutyric acid (GABA) in brain tissue, a very rapid and simple chromatographic procedure using high-performance liquid chromatography (HPLC) with electrochemical detection (ECD) in combination with precolumn o-phthalaldehyde (OPA) derivatization is described. Perchloric acid extracts of the tissue were mixed with OPA/beta-mercaptoethanol solution and the mixture was injected onto the HPLC system. The present method permits GABA assay within less than 3 min in one chromatographic run. Up to 100 samples a working day can be analyzed in the present method. The present method has been applied to the measurement of GABA levels in discrete brain regions of mice treated with aminooxyacetic acid and isoniazid.

[pH determination in human crevicular fluids. Examination of the pH meter and evaluation of the correlation between pH level and clinical findings or the microflora in each periodontal pocket]

The purpose of this study was to investigate the accuracy and reproduction of a microelectrode with a glass capillary, and to discuss the correlation between the pH level and the microflora in periodontal pockets or the clinical findings in the various stages of periodontal disease. The upper or lower anterior teeth of 34 patients with mild to severe periodontal disease were examined. Before the measurement, supragingival plaque was removed from each tooth. A special glass capillary was incorporated in the microelectrode to cover its tip, so that it would not touch the pocket walls or tooth surfaces during pH measurement. After the pH in the crevicular fluid was determined, subgingival plaque was collected with paper points from each periodontal pocket. This bacterial plaque was sonicated with saline solution, and examined under a phase contrast microscope with a calibrated eyepiece graticule to count and morphotype groupings of microorganisms as 1) coccoid forms, 2) rods, 3) filaments, 4) motile rods, 5) spirochetes or other cell types. Crevicular fluid flow measurements and clinical findings (pocket depth, and gingival inflammation) were also investigated. The following conclusions were drawn: The electrode with capillary was useful to determine the pH of the crevicular fluid clinically. A reduction in pH level was seen in deep pockets or severe gingival inflammation. A close correlation was seen between salivary and crevicular pH. The pH level was significantly positively related with the proportion of coccoid forms, but was negatively correlated with the proportion of motile organisms that are reported to be related with periodontal disease.

[In vitro study of bacterial invasion in radicular dentin]

The purpose of this study was to investigate whether plaque bacteria invade exposed radicular dentin after root planing or chemical root treatment in vitro. Pieces of dentin were cut out from impacted third molars. The surface of all dentin pieces was treated with sandpaper (#240) so as to make the surface roughness of dentin pieces equal to that of the root surface after root planing (RP surface). Half of the dentin pieces were treated with citric acid (pH 1.0) for 3 minutes (CA surface). After sterilization, each dentin piece was incubated at 37 degrees C in a culture medium inoculated with either S. mutans or S. sanguis. After 1, 3, 7 and 28 days of incubation, the invasion of microorganisms into the dentinal tubules was histologically examined using a light microscope. The following results were obtained. 1. The invasion of S. mutans and S. sanguis into the dentinal tubules was observed at 1, 3, 7 and 28 days. The depth and number of bacterial invasion into the dentinal tubules were positively correlated with incubation time on CA surfaces but not with RP surfaces. 2. The depth and the number of bacterial invasion into the dentinal tubules were higher on the CA surfaces than the RP surfaces. 3. Since the citric acid treatment of scaled and root planed root surfaces may accelerate bacterial invasion from treated root surfaces, the use of citric acid might be harmful in patients with inadequate plaque control.