A universal peroxyoxalate-chemiluminescence detection system for high performance liquid chromatography, available for a variety of mobile phases, has been developed. The system consisted of a dual-head short-stroke pump and a chemiluminescence detector. The standard conditions using bis(2,4,6-trichlorophenyl) oxalate (TCPO) as aryl oxalate were as follows. The first postcolumn solution was the mixture of 0.5 M imidazole-nitric acid (pH 7.5) and acetonitrile (1:4, v/v). The second was acetonitrile containing TCPO-hydrogen peroxide. These two solutions were delivered by the two pump-heads. After the pH of the column eluate was adjusted to the optimum range (6.5-7.5) by the first postcolumn solution, the solution was mixed with the second postcolumn solution. After flowing through a reaction coil, the chemiluminescence of the mixture was monitored. Using this system, a high sensitivity (fmol level) was obtained for perylene as an analyte with mobile phases having different pH values (2.0-8.0). Polycyclic aromatic hydrocarbons became detectable to a high sensitivity even after the column separation using an acidic mobile phase. The detection sensitivity of nitrated pyrenes after on-line electrochemical reduction using an acidic mobile phase was also increased. This system might be available for other aryl oxalates by some modifications of the postcolumn solutions.

Chromatography, High Pressure Liquid↗

PubMedDate not supplied

Chromatographic determination method for 1-nitropyrene and its metabolites in biological samples with fluorescence detection after on-line reduction.

A high performance liquid chromatographic (HPLC) method with fluorescence detection after on-line reduction for the determination of 1-nitropyrene (NP), 1-nitrosopyrene (NSP), 1-aminopyrene (AP) and N-acetylaminopyrene (AAP) has been developed. The reduction efficiency of NP and NSP on a zinc column was found to be higher than that of an electrochemical reducer. Using a HPLC system equipped with a zinc column (4.0 mm i.d. x 10 mm) and an imidazole/HClO4 (pH 6.8): acetonitrile mobile phase, detection limits (S/N = 3) of 20-30 fmol for NP, NSP and AP and 350 fmol for AAP were obtained. NP, NSP and AP were determined in the incubation mixture of NP and Salmonella typhimurium, YG1021, by this method. Time course studies showed that a large ratio of NP was metabolized in the pre-incubation step of the Ames test.

Acetonitriles↗

PubMedDate not supplied

Theoretical consideration on polarized photometric detection.

Previously, we developed a novel detector, a polarized photometric detector for optically active compounds, where two polarizers are set on either side of the UV-visible absorbance detector flow cell. In this paper, we present theoretical considerations on this method with several equations. If the inclined angle of the second polarizer is defined as alpha (left when alpha > 0 degree), the following equation is obtained: delta Abs = 2 log e.tan alpha.beta, where delta Abs is the change in absorbance and beta (magnitude of beta << alpha) is the angle of rotation of light passing through the cell containing the optically active compound. This equation suggests that delta Abs is proportional to the analyte concentration and that the dextro- and laevorotatory compounds are detected as positive and negative absorbance changes, respectively. The theoretical maximum signal to noise (S/N) ratio is obtained when alpha = 45 degrees (= 0.8 rad) and the smallest detection limit is 5 x 10(-5) degrees (S/N = 3) when the path length of the flow cell is 10 mm. This detector was successfully used in flow injection analysis (FIA) as well as HPLC for optically active compounds.

Chromatography, High Pressure Liquid↗

PubMedDate not supplied

A novel MR angiography technique: SPEED acquisition using half-Fourier RARE.

A novel MR angiography (MRA) method, swap phase encode extended data (SPEED), was developed. Two one-shot images with the phase-encode directions swapped were collected within a single breath-hold period and processed with a maximum intensity projection (MIP) to obtain an image. In this study, a long echo train two-dimensional rapid acquisition with relaxation enhancement (RARE) sequence with half-Fourier (half-RARE) was used to obtain the pulmonary MRA images. The MIP image obtained using the SPEED technique presented promising results for pulmonary vessels.

Fourier Analysis↗

PubMedDate not supplied

Neuroimaging study of myotonic dystrophy. I. Magnetic resonance imaging of the brain.

Magnetic resonance imaging scans of the brain were obtained in 13 patients with myotonic dystrophy, seven with congenital myotonic dystrophy and six with adult-type myotonic dystrophy. All seven patients with congenital myotonic dystrophy had ventriculomegaly and a low IQ (DQ). Cerebral white matter lesions were observed in six cases, a small corpus callosum in four cases, a small brainstem in two cases, and a cerebellar white matter lesion in one case. Cerebral white matter lesions were observed in five of the six cases with adult-type myotonic dystrophy of which one had ventriculomegaly. The IQ (DQ) was significantly lower in patients with congenital myotonic dystrophy than in those with adult-type myotonic dystrophy. The incidence of a small corpus callosum or ventricular enlargement was higher in congenital myotonic dystrophy than in adult-type myotonic dystrophy. These findings may be related to the presence of neurologic impairment in congenital myotonic dystrophy.

Adult↗

PubMedDate not supplied

Neuroimaging study of myotonic dystrophy. II. MRI measurements of the brain.

The brain of patients with adult type myotonic dystrophy was measured using MRI, and compared with age- and sex-matched controls. The width of the cerebrum, and the areas of the corpus callosum, pons and pituitary gland were significantly smaller in adult-type myotonic dystrophy than in the controls. The IQ of the patients with adult-type myotonic dystrophy was lower than that of controls. These results demonstrate a decreased volume of the brain and pituitary glands in myotonic dystrophy. These findings suggest a causal relationship for the mental retardation and endocrine dysfunction that may occur.

Adult↗

PubMedDate not supplied

Serial EEG and sleep polygraphic studies on lissencephaly (agyria-pachygyria).

We carried out serial EEG studies on 12 cases of lissencephaly (6 of agyria and 6 of pachygyria), polysomnograms being recorded in 8 of the 12 cases. Fourteen Hz sleep spindles appeared from early infancy in all cases. They were poorly observed after the age of 1 year, and 5-11 Hz high-amplitude rhythmic activity (HARA) of more than 300 microV appeared predominantly in place of the 14 Hz spindles. Both the 14 Hz spindles and HARA showed asymmetry, but the dominant cerebral area for both types of waves was much the same. Four of the 6 agyria cases showed hypsarrhythmia within the first 6 months after birth, 3 of the 4 cases showing asymmetric hypsarrhythmia at first. Their hypsarrhythmia consisted of very high-voltage 5-7 Hz slow sharp waves and delta waves. The EEG abnormalities transformed from hypsarrhythmia to focal spikes in the 6 pachygyria cases. The polygraphic study on 8 cases revealed that the proportion of REM sleep decreased in 3 cases and the REMs/min values decreased in 7. Infantile spasms occurred in 4 of the 8 cases. The REM/min values decreased in all of these 4 cases, and, furthermore, the proportion of REM sleep decreased in 3 of the 4 cases. These findings suggest that lissencephaly involves a disorder of the brainstem, and that the combination of brainstem lesions and severe cerebral dysplasia is important for the manifestation of infantile spasms in lissencephaly.

Aging↗

PubMedDate not supplied

Characteristics of auditory P300 in children: application of single trial analysis.

As, especially in children, cognitive function might vary from one stimulus to the other, even when the same target stimuli are presented in the oddball paradigm, we applied the single trial analysis adopting discrete Fourier transformation followed by inverse discrete Fourier transformation to the auditory P300 for the first time in children. In 9 children, age 9-13 years, a positive peak was clearly identified in approximately a quarter of the processed single sweep responses to target stimuli (single sweep P300), whereas it was observed less frequently for non-target stimuli. In 2 children of age 6 years, it was difficult to discriminate single sweep P300 from background EEG activities even in the processed data. As for the former group, the detection ratio of P300 in single sweep target responses ranged from 10.0 to 40.0%, and its mean latency and amplitude ranged from 311 to 348 ms and from 31.7 to 41.5 microV, respectively. There was a significant correlation between average data and single sweep data in terms of the P300 latency. However, the amplitude of P300 in the average data bore no relation to the detection ratio, mean amplitude or variability of latency among single sweep P300s. As compared with adult data previously reported, the detection ratio of single sweep P300 was lower and the P300 amplitude was higher in childhood. P300 in children, at least past puberty, can be analyzed by using the single trial method, which is expected to provide more information about the development of human higher brain functions, especially cognitive function.

Adolescent↗

PubMedDate not supplied

Proton magnetic resonance spectroscopy on childhood-onset dentatorubral-pallidoluysian atrophy (DRPLA).

To evaluate brain dysfunction of childhood-onset dentatorubral-pallidoluysian atrophy (DRPLA), three children with progressive myoclonus epilepsy, who were diagnosed as having DRPLA by DNA analysis, for the first time, underwent a study of proton magnetic resonance spectroscopy (1H-MRS). 1H-MRS obtained from both the parietal and basal ganglia regions disclosed markedly reduced ratios of N-acetylaspartate to both choline and creatine. Especially regarding the basal ganglia region, the latter (ratio of N-acetylaspartate to creatine) closely correlated to severity of genetic abnormality, i.e. number of expanded CAG repeats, suggesting that the degree of neuronal loss in the region strongly depends on genetic factors. 1H-MRS must be a valuable tool to clarify the pathophysiology of DRPLA.

Adolescent↗

PubMedDate not supplied

Characteristic evoked potentials in childhood-onset dentatorubral-pallidoluysian atrophy.

To determine the characteristics of multimodal evoked potentials (MEPs) in childhood-onset dentatorubral-palli-doluysian atrophy (DRPLA) we studied three DRPLA patients with progressive myoclonus epilepsy. Brainstem auditory evoked potentials showed reduced or absent brainstem components as well as delayed latencies. In addition, short latency somatosensory evoked potentials (S-SEPs) had prolonged central conduction time and reduced amplitude of cortical components. Two patients with symptom onset in the first decade of life had extremely enlarged flash visual evoked potentials with shortened latency even in the absence of giant SEPs. Therefore, children with progressive myoclonus epilepsy and the above MEP findings are likely candidates for childhood-onset DRPLA and should undergo DNA analysis for DRPLA.

Adolescent↗

PubMedDate not supplied

Significance of high levels of serum IgA and IgA-class circulating immune complexes (IgA-CIC) in patients with non-insulin-dependent diabetes mellitus.

Significance of serum IgA and IgA-class circulating immune complexes (IgA-CIC) elevation in patients with non-insulin-dependent diabetes mellitus (NIDDM) was described. Seventeen patients with NIDDM and 17 patients with diffuse mesangial proliferative glomerulonephritis without deposition of IgA (DPGN) as controls were examined. The levels of serum IgA in patients with NIDDM were significantly higher than those in patients with DPGN (p < or = 0.01). The levels of IgA-CIC in patients with NIDDM were also significantly higher than those in patients with DPGN (p < or = 0.01). Production of IgA derived from B cells and the proportion of IgA bearing B cells in patients with NIDDM were not significantly higher than those in patients with DPGN. Furthermore, the levels of IgA in pharyngeal washings from diabetic patients were not significantly higher than those for DPGN patients. Duration of diabetes, the level of HbA1c, and the presence of hypertension, microalbuminuria, or retinopathy showed no significant correlations with the levels of serum IgA or IgA-CIC in patients with NIDDM. It was postulated that the elevations of serum IgA and IgA-CIC were based on subclinical infection of the mucosa and/or deterioration of IgA clearance in patients with NIDDM.

Antibody Formation↗

PubMedDate not supplied

Morphological changes in rabbit corneal endothelium after surgical injury.

PURPOSE: To understand the responses of the corneal endothelium to different types of surgical insults, we chronologically investigated morphologic changes in rabbit endothelial cells after injury. METHODS: We performed a mechanical incision, epithelial ablation, or excimer laser irradiation on rabbit corneas and observed the changes in the endothelial cells for up to 2 weeks after surgery under a light microscope and an electron microscope. RESULTS: Although we observed enlargements of intercellular spaces between neighboring endothelial cells, intercellular adhesion complexes were maintained and the cells joined tightly near their apexes immediately after each procedure. We observed no signs of endothelial cell degeneration after the procedures, but we did observe many Golgi apparati, rough-surfaced endoplasmic reticula, and secreted granules, indicating that the cells had been activated. After each procedure, varying periods of time were required before the intercellular junctions and spaces returned to normal. CONCLUSION: These results suggest that the different kinds of surgical injuries affected the corneal endothelium in different ways, but that the early changes were reversible.

Animals↗