Expression and imprinting status of human PEG8/IGF2AS, a paternally expressed antisense transcript from the IGF2 locus, in Wilms' tumors

A large imprinted gene cluster in human chromosome 11p15.5 has been implicated in Beckwith-Wiedemann syndrome and Wilms' tumor. We have identified a paternally expressed imprinted gene, PEG8/IGF2AS, in this locus. It is transcribed in the opposite direction to the IGF2 transcripts and some genomic regions are shared with the IGF2 gene, as in the case of the mouse imprinted Igf2as gene reported previously by T. Moore et al. As to the relationship between these genomic regions, the human and mouse genes are very similar but there is no homology in their middle parts. Interestingly, PEG8/IGF2AS and IGF2 were found to be overexpressed in Wilms' tumor samples, at levels over ten and a hundred times higher than that in normal kidney tissues neighboring the tumors, respectively. These findings indicate that PEG8/IGF2AS is a good marker of Wilms' tumor and also suggest the possibility of PEG8/IGF2AS being one of the candidate Wilms' tumor genes.

[Radiculopathy and reversible axonopathy in a tetraplegic patient with meningeal carcinomatosis]

We report a 49-year-old tetraplegic woman with meningeal carcinomatosis secondary to breast cancer. Serial nerve conduction studies in the extremities revealed that the amplitudes of the sensory nerve action potentials (SNAP) and the compound muscle action potentials (CMAP) decreased rapidly within a few days after her admission. Plasma exchanges were done four times and restored the SNAP amplitudes to normal range. The CMAP amplitudes were also increased, but not to the normal range. These electrophysiologic changes were not associated with clinical improvement. Our patient's tetraplegia may be associated with a combination of two different mechanisms; reversible axonopathy caused by humoral factors that can be removed by plasma exchange, and irreversible radiculopathy due to direct cancer cell invasion.

Deficient cotinine formation from nicotine is attributed to the whole deletion of the CYP2A6 gene in humans

Nicotine is mainly metabolized to cotinine by cytochrome P450 (CYP) 2A6. Large interindividual differences in nicotine metabolism have been reported in humans. The purpose of this study was to clarify the relationship between the poor metabolism of nicotine and the existence of the CgammaP2A6v1 and CgammaP2A6v2 alleles, and a whole deletion allele of the CgammaP2A6 gene. The plasma concentrations of nicotine and cotinine were measured in 10 healthy subjects after each smoked one cigarette or chewed one piece of nicotine gum. One subject showed no detectable cotinine level in plasma when smoking and the lowest cotinine level when receiving nicotine gum. The subject was regarded as a poor metabolizer of nicotine by a probit analysis and was found to carry a homozygous whole deletion allele of the CgammaP2A6 gene. This is the first report to show that deficient cotinine formation in humans is attributed to the whole deletion of the CgammaP2A6 gene.

[Increased sensory nerve action potential amplitudes after plasma exchanges in a patient with acute sensory neuropathy]

Acute sensory neuropathy (ASN) is characterized by rapidly progressive sensory ataxia and areflexia without motor weakness. The disease has been thought to be due to dorsal root ganglionitis which leads to secondary sensory nerve axonal degeneration. In contrast, we here report a patient with ASN, in whom results of nerve conduction study pointed to a direct involvement of the sensory nerve axons. A 33-year-old man was admitted to our hospital because of a few days history of progressive numbness in his extremities and unsteadiness of gait. The results of motor nerve conduction studies were normal. Amplitudes of sensory nerve action potentials (SNAPs) decreased within a few days after admission, whereas sensory nerve conduction velocities were preserved. Cerebrospinal fluid examination showed an elevated protein level without pleocytosis. He was diagnosed as having ASN, and was treated with four times of plasma exchange which rapidly restored SNAP amplitudes to normal. However, a few days after the plasma exchanges, SNAP amplitudes decreased again. Second series of plasma exchanges one month after admission transiently increased SNAP amplitudes again but not to normal range. These electrophysiologic changes were not associated with clinical improvement. A sural nerve biopsy one month after admission revealed axonal degeneration. These findings suggest that our patient's sensory impairment is caused by reversible sensory axonopathy due to humoral factors that can be removed by plasma exchange, as well as acute irreversible ganglionopathy which may lead to secondary axonal degeneration as shown by sural nerve biopsy.

Antigenic characterization in ampiroxicam-induced photosensitivity using an in vivo model of contact hypersensitivity

Ampiroxicam (APX), a prodrug of piroxicam (PXM), has been reported to induce photosensitivity. Antigenic characterization of these photosensitivities, however, is still insufficient. The purpose of the present study was to elucidate further mechanism of photosenstivity induced by APX and PXM using an in vivo model of contact hypersensitivity in guinea pigs. Animals sensitized with ultraviolet-A (UVA)-irradiated 1% APX showed positive reaction in the patch testing to UVA-irradiated 1% APX and 1% thiosalicylate (TOS), while they were negative in challenge with UVA-irradiated 1% PXM, non-irradiated APX and PXM, whereas none of UVA-irradiated or non-irradiated APX and PXM showed positive patch test reaction in animals sensitized with UVA-irradiated 1% PXM or control vehicles. Animals sensitized with 1% TOS were successfully challenged by 1% TOS and cross-reacted with UVA-irradiated 1% APX; however, they failed to react with UVA-irradiated PXM, non-irradiated APX and PXM. Indeed, the in vitro study revealed that the concentration of APX was easily reduced by the increase of UVA irradiation dose, as compared with that of PXM. Interestingly, absorption spectrum of UVA-irradiated APX was similar to that of TOS, which is thought to be an active hapten of PXM. In the present study, we succeeded in the development of a novel animal model reflecting the clinical observations. Furthermore, these results suggested that contact hypersensitivity induced by UVA-irradiated APX is developed by photoproducts of APX itself, but not by the biotransformation of APX to PXM.

Effects of chronic administration of glucocorticoid on midazolam pharmacokinetics in humans

Midazolam (MDZ) is metabolized by CYP3A. Glucocorticoids are potent inducers of CYP3A in humans. The possible interaction between intravenous MDZ and chronically administered glucocorticoids was investigated during surgery in patients. MDZ (0.2 mg/kg) was administered intravenously to 8 patients taking glucocorticoid chronically and 10 patients not taking glucocorticoid. In patients taking glucocorticoid, the AUC0-infinity and CL of MDZ was decreased to 63.9% (16.3 +/- 10.5 vs 25.5 +/- 20.7 microg x min/mL) and increased to 127.5% (16.7 +/- 10.7 vs 13.1 +/- 8.3 mL/min/kg) of that in the control group, respectively. The terminal t1/2 values of MDZ were similar in two groups. In patients taking glucocorticoid, the AUC0-infinity of 1'-hydroxymidazolam (1'-OH MDZ) was 66.7% of that in the control group (7.6 +/- 2.6 vs 11.4 +/- 9.7 microg x min/mL), and the terminal t1/2 of 1'-OH MDZ was significantly (p < 0.01) decreased (1.8 +/- 0.5 vs 3.0 +/- 0.8 hr). Accumulative urinary excretion of 1'-OH MDZ glucuronide was increased to 157.6%. These observations might be results from induction of CYP3A4 and/or UDP-glucuronosyltransferase by glucocorticoids.

Effect of interstimulus interval on visual P300 in Parkinson's disease

OBJECTIVE

Visual event related potentials (ERPs) were studied during an oddball paradigm, to testify whether cognitive slowing in Parkinson's disease exists and to investigate whether cognitive information processing can be influenced by different interstimulus intervals (ISIs) of an oddball task in patients with Parkinson's disease and normal subjects.

METHODS

ERPs and reaction time were measured in 38 non-demented patients with Parkinson's disease and 24 healthy elderly subjects. A visual oddball paradigm was employed to evoke ERPs, at three different interstimulus (ISI) intervals: ISI(S), 1600 ms; ISI(M), 3100 ms; and ISI(L), 5100 ms. The effect of ISIs on ERPs and reaction time was investigated.

RESULTS

Compared with the normal subjects, P300 latency at Cz and Pz was significantly delayed after rare target stimuli in patients with Parkinson's disease only at ISI(L). Reaction time was prolonged in patients at all the three ISIs, compared with the normal controls. There was also significantly delayed N200 and reduced P300 amplitude at Cz and/or Pz to rare non-target stimuli in patients at the three ISIs, compared with the normal controls. During rare target visual stimulation, P300 latency and reaction time in the patients with Parkinson's disease and reaction time in the normal subjects were gradually prolonged as the ISI increased.

CONCLUSION

Prolonged N200 latency to rare non-target stimuli might indicate that automatic cognitive processing was slowed in Parkinson's disease. Cognitive processing reflected by P300 latency to rare target stimuli was influenced by longer ISI in patients with Parkinson's disease.

Encephalopathy in scleromyxedema

The authors monitored CSF findings for over 5 months in a patient with a fatal case of scleromyxedema and two episodes of encephalopathy. During both encephalopathy episodes, CSF protein and immunoglobulin G (IgG) levels were elevated without an increased IgG index or IgG synthesis rate. A CSF-dominant increase in the concentration of interleukin-6 (IL-6) also was noted during encephalopathy. These findings suggest a disruption of the blood-brain barrier and that IL-6 may play some role in mediating the encephalopathy. OFF

[Chronic sensory ataxic neuropathy associated with IgM antibody against b-series gangliosides including GD1b]

We described a 62-year-old man with a 10 years history of chronic sensory ataxic neuropathy. His laboratory investigations revealed elevated serum IgM with IgM kappa paraproteinemia, IgM antibody against b-series gangliosides including GD3, GD2, GD1b, GT1b, GQ1b, GQ1b alpha, and high titer of cold agglutinin. The clinical and serological features in our patient were compatible with the diagnosis of CANOMAD (chronic ataxic neuropathy with ophthalmoplegia, M-protein, agglutination, and disialosyl antibodies), proposed by Willison et al. IgM antibody against b-series gangliosides including GD1b appeared to play an essential role in developing autoimmune sensory ataxic neuropathy.

Visual event-related potential changes at two different tasks in nondemented Parkinson's disease

A visual oddball paradigm and an S1-S2 paradigm were employed to evoke event-related potentials (ERPs) in 38 nondemented Parkinson's disease (PD) patients and 24 healthy elderly subjects. Delayed N200 and reduced P300 amplitude in the whole PD sample were only found in the S1-S2 paradigm. Delayed N200 and reaction time in PD with short duration of illness were found only after the S1-S2 paradigm, which might be an early sign of cognitive changes in PD. This is the first study to apply an S1-S2 paradigm for a visual P300 test in PD and proved the value of this paradigm for detecting minor cognitive abnormalities. ERP changes were correlated with clinical features. Reduced P300 amplitude for the S1-S2 paradigm was significantly correlated with WAIS-R scores and gait disturbance. The correlation between P300 amplitude and clinical scores has rarely been discussed before. P300 latency during the oddball paradigm in PD was influenced by age at test, age at onset, and duration of illness. This may explain why P300 results in nondemented PD have varied among previous authors.

Stimulation of in vitro angiogenesis by hydrogen peroxide and the relation with ETS-1 in endothelial cells

The purpose of this study was to examine the effect of hydrogen peroxide (H2O2) on angiogenesis in cultured endothelial cells. Endothelial cells obtained from bovine thoracic aorta (BAECs) were cultured between two layers of collagen type I to measure the tube formation which is a marker for angiogenesis. Addition of H2O2 (0.1-10 microM) to endothelial cells for various periods increased the rate of tube formation. The maximum stimulation of the tube formation was obtained when cells were exposed to 1 microM H2O2 for 30 min, and the enhancement of tube formation was blocked by catalase (10 U/ml). Both proliferation and migration of BAEC which are known to affect angiogenesis, were also stimulated by the addition of H2O2 (0.1 and 1 microM). Thus relatively low concentrations of H2O2 stimulated angiogenesis, proliferation and migration. Ets-1 is a member of the ets gene family of transcription factors, which binds to the ets binding motif in the cis-acting elements and regulates the expression of certain genes such as proteases including urokinase plasminogen activator (u-PA) and matrix metalloproteinase-1 (MMP-1). Interestingly, H2O2 increased the ets-1 mRNA level in BAECs compared with the basal level. The H2O2-stimulated angiogenesis was completely blocked by an ets-1 antisense oligonucleotide, but not by a mismatched oligonucleotide. These findings indicate that low concentrations of H2O2 stimulate angiogenesis in BAECs, and the stimulation mechanisms may partially involve the enhancement of proliferation and migration. Moreover, the H2O2-induced angiogenesis is likely to be mediated by the transcription factor ets-1.

[The clinical usefulness of high-dose intravenous immunoglobulin therapy for chronic inflammatory demyelinating polyneuropathy and multifocal motor neuropathy]

To explore the optimum dose of intravenous immunoglobulin (i.v.Ig) for treating patients with chronic inflammatory demyelinating polyrneuropathy and multifocal motor neuropathy, we compared the usefulness of i.v.Ig among 3 treatment doses. Fifty-nine patients were randomly divided into three treatment dosage groups: 20 patients for Group I using 50 mg/kg/day x 5 days, 19 patients Group II using 200 mg/kg/day x 5 days, and 20 patients Group III using 400 mg/kg/day x 5 days. We assessed clinically and electrophysiologically the effectiveness of the treatment at 5 weeks after the initial infusion. For patients in Group I and II who had not improved (or worsened) with the first treatment, we gave a one-step larger dose in the second treatment (i.e. 200 mg/kg/day x 5 days for those who had been given 50 mg/kg/day x 5 days, 400 mg/kg/day x 5 days for those who had been given 200 mg/kg/day x 5 days) after more than 9 weeks. We found that 15% of the patients in Group I, 21% in Group II and 60% in Group III improved dose-dependently with the first intravenous immunoglobulin treatment. Seven (47%) of 16 patients in Group I and 4 (40%) of 11 patients in Group II improved after the second treatment with larger doses. Adverse reactions including chill sensation, fever, skin eruption and increase in blood GOT and GPT levels were transient and mild. One patient in Group III developed left hemiparesis showing the small infarction in the right thalamus during the course of the treatment, but the symptom was mild. In conclusion, the high-dose intravenous immunoglobulin therapy (400 mg/kg/day x 5 days) is useful for treating patients with CIDP and MMN, although care must be taken of the risk of causing cerebral infarctions.

Downgaze palsy and bilateral ptosis due to a thalamomesencephalic lesion

An unusual combination of downgaze palsy and bilateral ptosis occurred in a patient with central nervous system lymphoma involving bilateral thalamus and midbrain tegmentum. Following treatment with corticosteroids, the transition from total paralysis of downgaze to the supranuclear form was noted, along with alleviation of ptosis, followed by complete resolution of both. The results of serial magnetic resonance images were consistent with our interpretation that his initial eye signs were caused by the combined involvement of the bilateral rostral interstitial nucleus of the medial longitudinal fasciculus (supranuclear downgaze palsy) and the oculomotor subnuclei (nuclear palsy of the inferior recti and levator palpebrae muscles).

Defective auditory recognition after small hemorrhage in the inferior colliculi

We report the case of a male patient with a traumatic small hemorrhage partially involving the bilateral inferior colliculi without evidence of a temporal lobe lesion. He was unable to comprehend spoken words although he had intact speech production, reading and writing abilities. Comprehension of environmental sounds was also affected. Among the receptive musical abilities, discrimination of intensity, tone and rhythm were preserved, while recognition of melody was impaired. Audiometry showed normal thresholds for pure tone. Waves I-IV of brainstem auditory evoked potentials were elicited normally, whereas the wave V was elicited with reduced amplitude and prolonged latencies on both sides. The main component of middle latency auditory evoked potentials, which is evoked over both hemispheres by monaural stimulation to either side in normal subjects, was elicited only over the hemisphere contralateral to the ear receiving stimulation. Our patient's auditory findings were similar to those usually found in generalized auditory agnosia. Auditory agnosia is usually considered as a sign of a bitemporal cortical or subcortical disorder, but, in our patient, a brainstem disorder caused a disturbance of auditory recognition similar to auditory agnosia due to a bitemporal lesion. Our patient's auditory findings may belong to the category of a brainstem auditory-processing disorder brought on by a small hemorrhage in the inferior colliculi. In addition, the impairment in our patient implies that, in the neural processing of musical parameters, the decoding of intensity, tone and rhythm is accomplished at the level of inferior colliculus, whereas further cortical processing is necessary for the appropriate recognition of melody.

A novel variant of translation elongation factor-1beta: isolation and characterization of the rice gene encoding EF-1beta2

A rice gene encoding a novel isoform of translation elongation factor-1beta subunit (termed EF-1beta2) was isolated and characterized. The gene comprises of eight exons, and encodes a 226-amino-acid protein. Expression of EF-1beta2 mRNA is abundant in seeds and cultured cells, but is considerably low in the tissues of the rice seedling. Antiserum raised against an EF-1beta2 synthetic peptide detected a protein with a relative molecular mass of about 32 kDa, indicating the EF-1beta2 gene is actually expressed in rice tissues. EF-1beta2 showed a close similarity to the cognate subunits from plant (beta and beta').

Unilateral saccadic pursuit in patients with sensory stroke: sign of a pontine tegmentum lesion

BACKGROUND AND PURPOSE

Pure hemisensory syndrome can be caused by small strokes occurring in a number of regions, including the thalamus and pons. Differentiation of the pontine sensory syndrome from the thalamic sensory syndrome has generally been made on the basis of distribution of sensory loss and involvement of specific sensory modalities but not without uncertainties and difficulties. Because the pontine tegmentum plays a pivotal role in generating horizontal eye movement, we attempted to discriminate these 2 syndromes by analyzing horizontal eye movements in stroke patients with pure hemisensory syndrome.

METHODS

Horizontal saccade, pursuit, vestibulo-ocular reflex (VOR), and VOR cancellation (VORC) were evaluated using electro-oculography in 6 patients with hemisensory syndromes, 3 due to pontine stroke and 3 due to thalamic stroke, and all were verified by MRI or CT. In addition, somatosensory evoked potentials (SEPs) were recorded.

RESULTS

Smooth pursuit and VORC directed toward the side of the lesion were impaired unilaterally in patients with pontine sensory stroke, whereas those 2 movements were intact bilaterally in patients with thalamic sensory stroke. Saccade and VOR were preserved in all patients. SEPs were normal in all patients with pontine and thalamic sensory strokes. No difference was found in the pattern of sensory disturbance between the 2 types of stroke patients.

CONCLUSIONS

Ipsilateral impairment of the smooth pursuit system may be a sign of a pontine lesion in patients with hemisensory stroke.

[Clinical and pathological studies on nemaline myopathy in adulthood]

We examined 22 biopsied muscles from adult patients who had the histopathological characteristics of nemaline myopathy. In the first group, 13 patients had muscle weakness and/or skeletal abnormalities, such as high-arched palate, pes cavus and scoliosis which are often accompanied with the congenital nemaline myopathy. Their appropriate diagnosis had never been made until muscle biopsy was done, because of benign clinical course. In the second group, the symptoms of nine patients became manifest in adulthood and failed to show typical skeletal abnormalities. However, six muscle biopsies showed the histopathologic characteristics of congenital nemaline myopathy; abnormal fiber type distribution including type 1 fiber predominancy, type 1 fiber atrophy and type 2B fiber deficiency. Three patients remained in good health until adulthood when they developed muscle weakness with pathologic findings of nemaline myopathy. Accordingly, nemaline myopathy in adulthood can be categorized into three forms; the first two forms have clinical and pathologic evidence of the congenital benign form, whereas the symptoms are too mild to be noticed. The third form is not a hereditary disorder which may result from autoimmune pathophysiology.

Requirement of the glycosyl parts in platycodin D to stimulate pancreatic exocrine secretion

The whole structure of platycodin D is found to be essential to stimulate the volumetric increase in the pancreatic exocrine secretion, while the prosapogenins prepared from platycodin D increased only protein output of pancreatic juice.

Human buprenorphine N-dealkylation is catalyzed by cytochrome P450 3A4

Buprenorphine (BN) is a thebaine derivative with analgesic properties. To identify and characterize the cytochrome P450 (CYP) enzyme(s) involved in BN N-dealkylation, in vitro studies using human liver microsomes and recombinant human CYP enzymes were performed. Norbuprenorphine formation from BN was measured by a simple HPLC-UV assay method, without extraction. The BN N-dealkylation activities in 10 human liver microsomal preparations were strongly correlated with microsomal CYP3A-specific metabolic reactions, i.e. triazolam 1'-hydroxylation (r = 0.954), midazolam 1'-hydroxylation (r = 0.928), and testosterone 6beta-hydroxylation (r = 0.897). Among the eight recombinant CYP enzymes studied (CYP1A2, CYP2A6, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP2E1, and CYP3A4), only CYP3A4 could catalyze BN N-dealkylation. The apparent KM value for recombinant CYP3A4 was similar to that for human liver microsomes (23.7 vs. 39.3 +/- 9.2 microM). The demonstration of BN N-dealkylation by recombinant CYP3A4 and the agreement in the affinities (apparent KM values) of human liver microsomes and recombinant CYP3A4 provide the most supportive evidence for BN N-dealkylation being catalyzed by CYP3A4.

Efficient modification of a human chromosome by telomere-directed truncation in high homologous recombination-proficient chicken DT40 cells

Truncation of human chromosomes at desired sites by homologous recombination techniques enables functional and structural analyses of human chromosomes and development of human artificial chromosomes. However, this targeted truncation has been inefficient. We describe here an efficient method for targeted truncation in the chicken DT40 cells with a high homologous recombination rate. The human chromosome 22 was transferred into DT40 cells, where human telomeric repeat (TTAGGG)n was targeted to the LIF locus on the chromosome. Molecular and cytogenetic analyses showed that the predicted truncation at the LIF locus occurred in all of the targeted clones.

Involvement of CYP1A2 in mexiletine metabolism

AIMS

Mexiletine has been reported to be hydroxylated by cytochrome P450 2D6 (CYP2D6) in humans. However, the involvement of CYP1A2 in the metabolism of mexiletine has been proposed based on the interaction with theophylline which is mainly metabolized by CYP1A2. The aim of this study was to clarify the role of human CYP1A2 in mexiletine metabolism.

METHODS

Human CYP isoforms involved in mexiletine metabolism were investigated using microsomes from human liver and B-lymphoblastoid cells expressing human CYPs. The contributions of CYP1A2 and CYP2D6 to mexiletine metabolism were estimated by the relative activity factor (RAF).

RESULTS

Mexiletine p- and 2-hydroxylase activities in human liver microsomes were inhibited by ethoxyresorufin and furafylline as well as quinidine. Mexiletine p- and 2-hydroxylase activities in microsomes from nine human livers correlated significantly with bufuralol 1'-hydroxylase activity (r = 0.907, P < 0.001 and r = 0.886, P < 0.01, respectively). Microsomes of B-lymphoblastoid cells expressing human CYP1A2 exhibited lower mexiletine p- and 2-hydroxylase activities than those expressing human CYP2D6. It was estimated by RAF that the major isoform involved in mexiletine metabolism was CYP2D6, and the contribution of CYPIA2 to both mexiletine p- and 2-hydroxylase activities was 7-30% in human liver microsomes. However, the Km values of the expressed CYP1A2 (approximately 15 microM) were almost identical with those of the expressed CYP2D6 (approximately 22 microM) and human liver microsomes.

CONCLUSIONS

Mexiletine is a substrate of CYP1A2. The data obtained in this study suggest that the interaction of mexiletine with theophylline might be due to competitive inhibition of CYP1A2.

Inhibitory effects of antiarrhythmic drugs on phenacetin O-deethylation catalysed by human CYP1A2

AIMS

The aim of the study was to clarify whether the pharmacokinetic interaction between theophylline and mexiletine is mediated by inhibition of CYP1A2 and to assess the possible interaction potential of other antiarrhythmic drugs with drugs metabolized by CYP1A2.

METHODS

The inhibitory effects of mexiletine and 10 antiarrhythmic drugs on phenacetin O-deethylation, a marker reaction of CYP1A2, were studied using human liver microsomes and cDNA-expressed CYP1A2.

RESULTS

Propafenone and mexiletine inhibited phenacetin O-deethylation with IC50 values of 29 and 37 microM, respectively. Disopyramide, procainamide and pilsicainide produced negligible inhibition of phenacetin O-deethylation (IC50 >1 mM). Amiodarone, bepridil, aprindine, lignocaine, flecainide and quinidine inhibited phenacetin O-deethylation in a concentration-dependent manner, although the inhibitory effects were relatively weak with IC50 values ranging from 86 to 704 microM. Propafenone and mexiletine selectively abolished the high-affinity component of phenacetin O-deethylation in human liver microsomes. In addition, propafenone and mexiletine inhibited phenacetin O-deethylation catalysed by cDNA-expressed CYP1A2.

CONCLUSIONS

These data suggest that, among the antiarrhythmic drugs studied, propafenone and mexiletine are relatively potent inhibitors of CYP1A2, which may cause a drug-drug interaction with drugs metabolized by CYP1A2.

[Guillain-Barré syndrome with nerve conduction blocks at multiple common entrapment sites that rapidly disappeared after plasmapheresis]

Nerve conduction blocks (NCBs) in Guillain-Barré syndrome (GBS) are frequently found at the distal terminals, proximal segments, and common entrapment sites of peripheral nerves. NCBs at distal terminals and proximal segments are considered to be due to vulnerability of the sites to the humoral factors of GBS because of relative blood-nerve barrier deficiencies. In contrast, it is not clear whether NCBs at common entrapment sites in GBS are due to a vulnerability to humoral influences or to direct mechanical compression injuries. We report a case of a 22-year-old man with GBS. His electrophysiologic examination revealed NCBs at multiple common entrapment sites. All conduction blocks rapidly disappeared after plasmapheresis, in parallel with clinical improvement. The patient was ambulatory throughout the clinical course, suggesting that his common entrapment sites remained free from compression injuries. Rapid improvement by plasmapheresis suggested that there were no demyelinative histologic changes in the NCB sites. Such NCBs may be caused by some humoral factor that is removed by plasmapheresis. Therefore, the common entrapment sites in our patient may have been especially vulnerable to the humoral factor of GBS.

Cytochrome P450 2C9 catalyzes indomethacin O-demethylation in human liver microsomes

Indomethacin is a widely used nonsteroidal anti-inflammatory drug. We studied the human cytochrome P450 (CYP) isoform responsible for indomethacin O-demethylation, the major metabolic pathway for indomethacin. For indomethacin O-demethylase activities, the KM value was 34.6 +/- 5.4 muM and the Vmax value was 14.1 +/- 3.9 pmol/mg/min in human liver microsomes (N = 4). Indomethacin O-demethylase activity in human liver microsomes was competitively inhibited by sulfaphenazole, (S)-warfarin, and tolbutamide and was not affected by alpha-naphthoflavone, (S)-mephenytoin, or erythromycin. Indomethacin O-demethylase activities in microsomes from nine human livers were significantly correlated with tolbutamide hydroxylase activities (r = 0.750, p < 0.05) and not with (S)-mephenytoin 4'-hydroxylase activities. When the capacity for indomethacin O-demethylation in microsomes of B lymphoblastoid cells expressing human CYPs was investigated at an indomethacin concentration of 5 microM, cDNA-expressed CYP2C9 exhibited 6-fold greater activity than did CYP2C19. At an indomethacin concentration of 50 microM, cDNA-expressed CYP1A2 and CYP2D6 also exhibited slight activities. The KM values were 9.9 +/- 1.2 and 117.1 +/- 13.8 microM and the Vmax values were 0.33 +/- 0.05 and 0.24 +/- 0.04 pmol/min/pmol CYP in microsomes with cDNA-expressed CYP2C9 and CYP2C19, respectively (N = 4). Considering the 16-fold higher intrinsic clearance of CYP2C9, compared with that of CYP2C19, and these expression levels in human livers, the contribution of CYP2C19 to indomethacin O-demethylation was considered to be negligible. Indomethacin appears to be O-demethylated exclusively by CYP2C9 in humans.

Identification of the Meg1/Grb10 imprinted gene on mouse proximal chromosome 11, a candidate for the Silver-Russell syndrome gene

In a systematic screen for maternally expressed imprinted genes using subtraction hybridization with androgenetic and normal fertilized mouse embryos, seven candidate maternally expressed genes (Megs) have been isolated, including the H19 and p57(Kip2) genes that are known to be maternally expressed. Herein, we demonstrate that an imprinted gene, Meg1, is apparently identical to Grb10 (growth factor receptor-bound protein 10), which is located on mouse proximal chromosome 11. Grb10 protein was reported to bind to the insulin receptor and/or the insulin-like growth factor (IGF) I receptor via its src homology 2 domain and to inhibit the associated tyrosine kinase activity that is involved in the growth promoting activities of insulin and IGFs (IGF-I and -II). Thus, it is probable that Meg1/Grb10 is responsible for the imprinted effects of prenatal growth retardation or growth promotion caused by maternal or paternal duplication of proximal chromosome 11 with reciprocal deficiencies (MatDp.prox11 or PatDp.prox11), respectively. In the human, it has been reported that the maternal uniparental disomy 7 is responsible for the Silver-Russell syndrome (SRS) whose effects include pre- and postnatal growth retardation and other dysmorphologies. The human homologue GRB10 on chromosome 7q11.2-12 is a candidate gene for Silver-Russell syndrome.

Diastereospecific kinetics of nicotine N'-oxidation in rat liver microsomes

1. In kinetic studies, both Eadie-Hofstee plots for cis- and trans-nicotine-1'-N-oxide formation from nicotine in rat liver microsomes were linear. For the formation of cis- and trans-nicotine-1'-N-oxide, the apparent K(m) were 0.240 +/- 0.069 and 1.524 +/- 0.951 mM respectively. Corresponding Vmax were 1.52 +/- 0.48 and 1.19 +/- 0.74 nmol/mg/min respectively. 2. The formation of cis-nicotine-1'-N-oxide was greater than the formation of trans-nicotine-1'-N-oxide in rat liver microsomes and the intrinsic clearance of cis-nicotine-1'-N-oxide formation was 8.1-fold greater than that of trans-nicotine-1'-N-oxide formation. 3. The formation of both cis- and trans-nicotine-1'-N-oxide in rat liver microsomes was inhibited by the addition of 1-(1-naphthyl)-2-thiourea or by heat-treatment of microsomes. 2-Diethylaminoethyl-2, 2-diphenylvalerate (SKF525A) and carbon monoxide did not affect these activities even at high concentrations. 4. Formations of cis- and trans-nicotine-1'-N-oxide correlated significantly with each other (r = 0.862, p < 0.01). These results suggested that the same flavin-containing monooxygenase (FMO) isoform is responsible for the formation of cis- and trans-nicotine-1'-N-oxide in rat liver.

Expression of RANTES by normal airway epithelial cells after influenza virus A infection

The chemokine regulated on activation, normal T cells expressed and secreted (RANTES), is a C-C chemokine and a potent chemoattractant for monocytes, T lymphocytes, basophils, and eosinophils. Its expression by human airway epithelium has been demonstrated both in vitro and in vivo. We investigated whether RANTES is expressed by normal human airway epithelial cells after influenza viral infection and examined its bioactivity. Epithelial cells were obtained from bronchial tissue or nasal polyps of patients who had undergone lobectomy for lung cancer or polypectomy for nasal polyps. These cells were cultured by the outgrowth method. Cultured cells were infected with influenza virus A (subtype H3N2) after which the supernatants and the cells were collected 8 to 72 h after infection. RANTES mRNA (messenger RNA) was analyzed by the reverse transcriptase-polymerase chain reaction and Southern blot analysis of its product. Concentrations of RANTES in the supernatants were analyzed by enzyme-linked immunosorbent assay. RANTES protein and mRNA were not detected in the media of uninfected cells. PCR products for RANTES were clearly detected in nasal and bronchial epithelial cells 24 h after infection. Southern blot analysis confirmed that the PCR products were indeed specific for RANTES mRNA. Twenty-four to 72 h after infection, significant levels of RANTES protein were detected in culture media. We also investigated the chemotactic activity of the supernatant of cultured cells. The supernatant of the cells 48 h after infection had potent chemotactic activity for eosinophils, which was attenuated by the addition of anti-RANTES antibodies. These findings suggest that influenza virus infection may induce expression of bioactive RANTES by normal human bronchial and nasal epithelial cells.

Nicotine metabolism in liver microsomes from rats with acute hepatitis or cirrhosis

Nicotine exerts a number of physiological effects. Nicotine is absorbed through the lungs with smoking and is rapidly metabolized in humans. Although it is mainly metabolized in the liver, the effects of liver injuries on nicotine metabolism are not clear. The purpose of this study was to clarify the effects of liver injuries on nicotine metabolism. Rats were treated with D-galactosamine (GalN) or thioacetamide (TA), to induce acute hepatitis or liver cirrhosis, respectively. Serum transaminase levels were significantly elevated in model rats with both types of liver injury. Cytochrome P450 (CYP) and cytochrome b5 contents in liver microsomes were decreased significantly in TA-treated cirrhotic rats but not in GalN-treated hepatitic rats. The major metabolic pathways of nicotine, i.e. cotinine formation catalyzed by CYP and nicotine-1'-N-oxide formation catalyzed by flavin-containing monooxygenase, were investigated in these rat liver microsomes. Formation of cotinine and nicotine-1'-N-oxide from nicotine was not changed in GalN-treated hepatitic rats, in comparison with the controls, but was significantly decreased in TA-treated cirrhotic rats. By immunoblotting, decreases in CYP1A2, CYP2B2, CYP2C, and CYP2E1 protein were recognized in liver microsomes from TA-treated cirrhotic rats. It was also shown that the maximal velocity values for nicotine-1'-N-oxide formation in TA-treated cirrhotic rats were significantly decreased, compared with the controls. These results suggested that the reduction of nicotine metabolism in cirrhosis was due to decreases in CYP and flavin-containing monooxygenase protein expression levels.

Apoptotic nuclear degeneration in Marinesco-Sjögren syndrome

In 12 patients with the clinical characteristics of Marinesco-Sjögren syndrome including an autosomal recessive inheritance, congenital cataracts, mental retardation, cerebellar ataxia and progressive muscle weakness, the most common pathological finding was rimmed vacuole formation comprising from 0.1% to 10% of fibers in their muscle biopsy samples. The nuclear changes varied from condensed chromatin granules to vacuolation with amorphous inclusions which were predominantly seen in younger patients with prominent rimmed vacuoles, suggesting a close relationship between nuclear change and rimmed vacuole formation. From the severe destructive changes in nuclei, we speculated that the nuclear changes in Marinesco-Sjögren syndrome play a primary role in muscle degeneration resulting in myofibrillar disorganization and rimmed vacuole formation. In 2 patients, the TUNEL method demonstrated scattered myonuclei with fragmented DNA, but "ladder formation" was not found, probably because of the small numbers of nuclei with fragmented DNA. Nuclear degeneration with focal myofibrillar degeneration seen in these muscle samples suggests that the apoptotic process may occur in muscle disorders, especially in diseases with rimmed vacuole formation.

Stimulative effects of saponin from kikyo-to, a Japanese herbal medicine, on pancreatic exocrine secretion of conscious rats

Our previous report stated that kikyo-to, a Japanese herbal medicine, consisting of the roots of Platycodon grandiflorum and Glycyrrhiza sp., stimulates the pancreatic exocrine secretion of conscious rats. The present study focused on the effective components of kikyo-to and the mechanism of stimuli to pancreatic secretion of rats. When 10 to 100 mg of platycodin D, a saponin from the root of Platycodon grandiflorum, was intragastrically administered, the pancreatic secretion of rats was stimulated. At the same time, the plasma CCK concentration increased. On the other hand, the stimulative effects of glycyrrhizin, a saponin from the root of Glycyrrhiza sp. were weak compared to platycodin D. The effects of 10 mg/kg of platycodin D on pancreatic secretion were inhibited by loxiglumide (50 mg/kg, i.g.), a CCK receptor antagonist. In contrast, the suppressive effect of atropine (300 micrograms/kg/h, i.v.) on pancreatic secretion was reduced by administering 10 mg/kg of platycodin D. In addition, up to 1 mM of platycodin D did not inhibit the trypsin activities in vitro. In conclusion, kikyo-to serves to stimulate pancreatic exocrine secretion mainly because platycodin D causes gastrointestinal hormones, particularly, CCK to be released from the duodenum.

Peg5/Neuronatin is an imprinted gene located on sub-distal chromosome 2 in the mouse

We have established a systematic screen for imprinted genes using a subtraction-hybridization method with day 8.5 fertilized and parthenogenetic embryos. Two novel imprinted genes, Peg1/Mest and Peg3, were identified previously by this method, along with the two known imprinted genes, Igf2 and Snrpn. Recently three additional candidate imprinted genes, Peg5-7 , were detected and Peg5 is analyzed further in this study. The cDNA sequence of Peg5 is identical to Neuronatin, a gene recently reported to be expressed mainly in the brain. Two novel spliced forms were detected with some additional sequence in the middle of the known Neuronatin sequences. All alternatively spliced forms of Peg5 were expressed only from the paternal allele, confirmed using DNA polymorphism in a subinterspecific cross. Peg5/Neuronatin maps to sub-distal Chr 2, proximal to the previously established imprinted region where imprinted genes cause abnormal shape and behavior in neonates.

Bufalin reduces the level of topoisomerase II in human leukemia cells and affects the cytotoxicity of anticancer drugs

When human leukemia HL-60 cells were treated with 10(-7) M bufalin, the amounts of both topoisomerase (topo) II alpha and II beta and the activity of topo II decreased markedly and were almost undetectable 18 h after the start of treatment. The level of topo II mRNA started to decrease immediately after the start of treatment with bufalin, with a subsequent decrease in the amount of topo II alpha protein. These changes preceded the fragmentation of DNA, a typical feature of apoptosis. The results suggest that bufalin caused a marked decrease in the steady-state level of topo II alpha mRNA, which led to a decrease in the amount and activity of the enzyme and to the induction of apoptosis. A reduction in the level of topo II alpha by bufalin was also observed in other lines of human leukemia cells such as ML1 and U937. The results were exploited to potentiate the effects of cisplatin and retinoic acid (RA) on HL-60 cells: pretreatment of HL-60 cells with 10(-7) M bufalin for 6 h increased the inhibitory effects of cisplatin and RA on cell growth and enhanced the induction of cell death.

The protooncogene product, PEBP2beta/CBFbeta, is mainly located in the cytoplasm and has an affinity with cytoskeletal structures

The Pebpb2/Cbfb gene encodes the non-DNA binding beta subunit of the heterodimeric transcription factor, PEBP2/CBF, and has been implicated in a subtype of human acute myeloid leukemia, as well as being indispensable for the development of definitive hematopoiesis in the murine fetal liver. By examining a subcellular localization of the PEBP2beta/CBFbeta protein in tissue culture cells, we could reveal an additional aspect of the protein other than to be a subunit of a transcription factor. Immunoblot and immunocytochemical staining showed that PEBP2beta/CBFbeta was mostly present in the cytoplasm. This PEBP2beta/CBFbeta was free from its DNA-binding partner, the alpha subunit of PEBP2/CBF, as judged by the electrophoretic mobility shift assays. Furthermore, a significant amount of PEBP2beta/CBFbeta was retained in the cytoskeleton preparation after detergent extraction of the cells and was found by double immunofluorescence to colocalize with the F-actin on stress fibers and the vinculin in membrane processes. Thus, the present study extends PEBP2beta/CBFbeta to be a cytoskeleton-affinitive as well as nuclear protein. The implications of these results are discussed.

Treatment of U937 cells with bufalin induces the translocation of casein kinase 2 and modulates the activity of topoisomerase II prior to the induction of apoptosis

The treatment of human leukemia U937 cells with 10(-8) M bufalin in the absence of serum resulted in the immediate translocation of casein kinase 2 (CK 2) from the cytoplasm to the nucleus, as determined by confocal laser-scanning microscopy. Concomitantly, the activity of topoisomerase (topo) II, as determined by monitoring activities specific to this enzyme such as DNA relaxation, DNA decatenation, and topo II-mediated DNA cleavage, was enhanced. The activity reached a maximum after 3 h and then decreased markedly after treatment with bufalin for 9 h. The amount of a complex of CK 2 and topo IIalpha in U937 cells was estimated by immunoprecipitation with antibodies raised against subunits of CK 2 and against topo IIalpha. The amount increased just after the start of treatment with bufalin and reached a maximum at 6 h. The results suggest that the topo IIalpha in the complex might have been phosphorylated by the translocated CK 2 and that the topo activity was stimulated by such phosphorylation. Apoptotic U937 cells with fragmented nuclei were observed between 9 and 12 h after the start of treatment using 10(-8) M bufalin. Therefore, it appears that the bufalin signal was transmitted to the nucleus by the translocation of CK 2, which formed a complex with topo IIalpha and modulated the activity of this enzyme, leading to the induction of apoptosis.

Changes in glutamate receptors, c-fos mRNA expression and activator protein-1 (AP-1) DNA binding activity in the brain of phenobarbital-dependent and -withdrawn rats

We studied changes in glutamate receptors, expression of immediate early genes, and AP-1 DNA binding activity in the brains of phenobarbital (PB)-dependent and -withdrawn rats to investigate the possible involvement of activation of glutamate receptors in PB withdrawal syndrome. PB-dependent rats were prepared by feeding drug-admixed food for 5 weeks. Autoradiographic analysis showed that binding of [3H(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imin e (MK-801), an antagonist of N-methyl-D-aspartic acid (NMDA) receptors, increased significantly in the cerebral cortices of PB-dependent and 24-h-withdrawn rats. However, [3H]MK-801 binding in the hippocampus and [3H]6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and [3H]kainic acid binding in the hippocampus and cerebral cortex were essentially unchanged in both groups. PB withdrawal seizures were followed by increased expression of c-fos mRNA in the hippocampus and cerebral cortex and of c-jun mRNA in the cerebral cortex. The induction of c-fos and c-jun mRNA was suppressed by administration of MK-801. Furthermore, PB withdrawal enhanced AP-1 DNA binding activity in the brain. The present findings suggest functional enhancement of glutamatergic neurotransmission during the development of PB withdrawal syndrome.

[Familial Creutzfeldt-Jakob disease with the heterozygous point mutation at codon 200 of the prion protein gene (Glu-->Lys)--report of CJD200 brothers of Yamanashi Prefecture origin]

We report two brothers with familial Creutzfeldt Jakob disease (CJD) having a heterozygous point mutation at codon 200 of the prion protein gene (Glu-->Lys): CJD200. The brothers were born in Kitakoma-gun, Yamanashi Prefecture. Patient 1, a 62-year-old man, developed CJD in 1995 and died nine months later. Patient 2, his brother, developed CJD200 at the age of 58 in 1982 and died 13 months later. They both exhibited rapidly progressive dementia with myoclonus and periodic synchronous discharges on electroencephalograms and became bedridden with three or four months. DNA analysis of peripheral blood cells of patient I showed a point mutation in the prion protein gene at codon 200: GAG-->AAG (Glu-->Lys). Five families with CJD200, 11 patients, have been reported in Japan to date, and nine of the patients from four families were born in Yamanashi Prefecture and vicinity. Our patients were born in the same area. We suspect that there is a cluster of CJD200 in Yamanashi Prefecture and vicinity. In Europe and America the phenotype of CJD200 has been reported to be heterogeneous, whereas the clinical features in Japanese cases are fairly homogeneous. We suspect that these patients have a common ancestor with a codon 200 mutation, and that that explains why the phenotypes are homogeneous.

Human PEG1/MEST, an imprinted gene on chromosome 7

The mouse Peg1/Mest gene is an imprinted gene that is expressed particularly in mesodermal tissues in early embryonic stages. It was the most abundant imprinted gene among eight paternally expressed genes (Peg 1-8) isolated by a subtraction-hybridization method from a mouse embryonal cDNA library. It has been mapped to proximal mouse chromosome 6, maternal duplication of which causes early embryonic lethality. The human chromosomal region that shares syntenic homology with this is 7q21-qter, and human maternal uniparental disomy 7 (UPD 7) causes apparent growth deficiency and slight morphological abnormalities. Therefore, at least one paternally expressed imprinted gene seems to be present in this region. In this report, we demonstrate that human PEG1/MEST is an imprinted gene expressed from a paternal allele and located on chromosome 7q31-34, near D7S649. It is the first imprinted gene mapped to human chromosome 7 and a candidate for a gene responsible for primordial growth retardation including Silver-Russell syndrome (SRS).

[Electroencephalogram]

Electroencephalographic (EEG) changes are generally prominent in patients with encephalitis. In most of acute encephalitis, the EEG is characterized by non-specific diffuse slow activity. However several diseases such as herpes simplex encephalitis, slow virus infection or prion disease often show periodic EEG abnormalities, such as periodic synchronous discharges (PSD) and periodic lateralized epileptiform discharges (PLED). These findings are sometimes diagnostic, although the abnormality is not disease specific. EEG is often helpful in following up the clinical course of illness and in evaluating therapeutic effects.