Loss of heterozygosity of the retinoblastoma gene in liver cirrhosis accompanying hepatocellular carcinoma

Carcinogenesis is a multistep process. Most hepatocellular carcinoma (HCC) is preceded by liver cirrhosis, but the genetic changes involved in cirrhosis are not known well. The present study was conducted to evaluate aberration of the retinoblastoma (RB) gene in HCC and adjacent non-tumorous liver using 22 patients with chronic liver damage accompanying HCC. The specimens obtained by microdissection from paraffin-embedded tissues were analyzed using an assay based on the polymerase chain reaction for highly polymorphic nucleotide sequences of microsatellites in the RB gene. Out of 22 cases, 15 showed constitutional heterozygosity for the microsatellite markers. In 11 (73.3%) of these 15 informative cases, the primary HCC foci showed loss of heterozygosity (LOH). In 8 of these 11 doubly informative (informative and LOH-positive in primary HCC) cases, LOH was found in 20 (64.5%) of 31 microdissected non-tumorous foci. All of the non-tumorous foci showing RB loss were cirrhotic lesions but there were no foci of chronic hepatitis. The remaining 4 cases without LOH in HCC foci showed no LOH in non-tumorous lesions. In our study, LOH of the RB gene was frequently observed in liver cirrhosis surrounding tumor.

Generation and characterization of mice lacking gastrin-releasing peptide receptor

Gastrin-releasing peptide (GRP) is a mammalian bombesin-like peptide which is widely distributed in the central nervous system as well as in the gastrointestinal tract. GRP binds to its high affinity receptor (GRPR) to elicit a wide spectrum of biological effects on behavior, digestion, and metabolism. To define the in vivo function of GRPR, we generated GRPR null mutant mice by gene targeting. The intracerebroventricular administration of GRP caused hypothermia in wild-type mice, but not in mutant mice. The GRPR deficient mice showed significantly increased locomotor activity during the dark period, and social responses scored by sniffing, mounting, and approaching behaviors against an intruder. Aggressive scores such as fighting and biting were not altered in the mutant mice. These phenotypes were observed in mice generated from two independent ES cell clones and backcrossed to a C57BL/6J background. The GRPR deficient mice should be useful for studying the bombesin system in vivo.

Tidal volume effects on surfactant treatment responses with the initiation of ventilation in preterm lambs

We hypothesized that initiation of ventilation in preterm lambs with high volumes would cause lung injury and decrease the subsequent response to surfactant treatment. Preterm lambs were randomized to ventilation for 30 min after birth with 5 ml/kg (VT5), 10 ml/kg (VT10), or 20 ml/kg (VT20) tidal volumes and then ventilated with approximately 10 ml/kg tidal volumes to achieve arterial PCO2 values of approximately 50 Torr to 6 h of age. VT20 lambs had lower compliances, lower ventilatory efficiencies, higher recoveries of protein, and lower recoveries of surfactant in alveolar lavages and in surfactant that had decreased compliances when tested in preterm rabbits than VT5 or VT10 lambs. Other lambs randomized to treatment with surfactant at birth and ventilation with 6, 12, or 20 ml/kg tidal volumes for 30 min had no indicators of lung injury. An initial tidal volume of 20 ml/kg decreased the subsequent response to surfactant treatment, an effect that was prevented with surfactant treatment at birth.

Two differential effects of cyclic adenosine 3',5'-monophosphate on IL-5 production by antigen-specific human T cell line

It has been proven that increasing cyclic adenosine 3',5'-monophosphate (cAMP) in human helper T cells results in decreased production of interleukin (IL)-2. As we have recently found that IL-2 stimulates IL-5 production, the effects of cAMP on IL-5 synthesis of T cells was investigated in this study. Prostaglandin E2 and forskolin raised intracellular cAMP level of Dermatophagoides farinae extract-reactive human T cell line and inhibited T cell receptor-stimulated IL-5 production. The cAMP analog, dibutyryl-cAMP, also inhibited IL-5 production, whereas the protein kinase A inhibitor, H-89, enhanced IL-5 production. The IL-5 production was completely suppressed by anti-IL-2 neutralizing antibody. Recombinant human IL-2 itself induced IL-5 production, suggesting that IL-5 production stimulated through T cell receptor is dependent on the autocrine production of IL-2. Prostaglandin E2, forskolin and dibutyryl-cAMP enhanced but H-89 suppressed recombinant human IL-2-induced IL-5 production. Prostaglandin E2 suppressed T cell receptor-stimulated mRNA expression of IL-2 as well as IL-5 in the T cell line, whereas it potentiated IL-5 mRNA expression stimulated by recombinant human IL-2. These results suggest that the inhibitory effect of cAMP on IL-5 production is mediated by the suppression of IL-2 production. On the contrary, IL-2-induced IL-5 synthesis is enhanced by increasing cAMP. Our study clearly indicated that cAMP regulates IL-5 production of human T cells by two differential effects.

Expression of a glutamate transporter subtype, EAAT4, in the developing human cerebellum

A glutamate transporter subtype, EAAT4, is closely related to removal of glutamate from the synaptic cleft. Immunohistochemistry for EAAT4 demonstrated the specific distribution and localization of its expression in the developing human cerebellum. Purkinje cells showed faint EAAT4 immunostaining at 17 gestational weeks (GW), which became increasingly intense from 23 GW to the infantile period. In the late fetal to early infantile periods, Purkinje cells showed marked immunoreactivity. After the late infantile period, EAAT4 immunoreactivity was the same in extent as in the adult pattern. Its intracellular localization also changed with development. EAAT4 immunoreactivity was demonstrated in the short processes of Purkinje cells in the early embryonic period, in the cell bodies and dendrites in the late fetal to early infantile periods, and then in the spines after the late infantile period. In the adult cerebellum, immunoreactivity was detected strongly in the spines of Purkinje cells and weakly in the cell bodies. No immunoreactivity was found in the axons or axon terminals of the cells. Thus, the glutamate transporter exhibits developmental changes in its distribution in the cerebellum and its localization in Purkinje cells. EAAT4 immunoreactivity may be related to the dendritic arborization of cells in the molecular layer.

Biphasic effects of carbamazepine on the dopaminergic system in rat striatum and hippocampus

To clarify the effects of carbamazepine (CBZ) on dopamine (DA) release and their metabolism, the extracellular and total levels of DA, its metabolites (DOPAC and HVA) and precursor, 3,4-dihydroxyphenylalanine (DOPA) in the striatum and hippocampus were studied. DA re-uptake and DOPA accumulation in the striatum and hippocampus, and monoamine oxidase (MAO) activities were also determined. After acute and chronic administrations of CBZ, the plasma concentration of CBZ associated with therapeutic activity increased the extracellular and total levels of all substances determined, whereas supratherapeutic concentration of CBZ decreased extracellular and total levels of all substances. Neither therapeutic nor supratherapeutic concentrations of CBZ affected MAO-A nor -B activities, nor DA re-uptake. DOPA accumulation caused by NSD1015 was inhibited by therapeutic and supratherapeutic concentrations of CBZ. These results suggest that a therapeutic concentration of CBZ enhances DA turnover, whereas a supratherapeutic concentration of CBZ inhibits DA turnover. These effects of CBZ on dopaminergic systems may be, at least partially, involved in the mechanisms of action of CBZ.

Effects of cimetidine on acute gastric mucosal injury induced by ischemia-reperfusion in rats

We investigated the effects of cimetidine on acute gastric mucosal injury induced by ischemia-reperfusion in rats. Under pentobarbital anesthesia, the celiac artery was clamped for 30 min and reperfused for 60 min. Cimetidine, famotidine and omeprazole caused a dose-dependent suppression in the total area of erosions that were induced by ischemia-reperfusion. Whereas, none of them inhibited the increase in thiobarbituric acid-reactive substances in the stomach, as an index of lipid peroxidation. The inhibitory effect of intraperitoneally administered cimetidine on mucosal damage was abolished by continuous luminal perfusion with HCl solution (pH 1.5, 1 ml/min) during ischemia-reperfusion, while luminal perfusion with the solution containing HCl and cimetidine (3 mmol/l) significantly reduced the total area of erosions compared to luminal perfusion with HCl solution alone. Cimetidine (3 mmol/l) inhibited hydroxyl radical-induced lipid peroxidation of human erythrocyte membranes by 60% in vitro. These results indicate that cimetidine possesses a protective effect against acute gastric mucosal injury induced by ischemia-reperfusion not only due to the suppression in gastric acid secretion, but also due to the antioxidant action when it is present at a high concentration in the intragastric environment.

Effects of non-toxic and toxic concentrations of phenytoin on monoamines levels in rat brain

To clarify the mechanisms of the antiepileptic activity of phenytoin (PHI), the effects of PHT on extracellular and total levels of monoamines (dopamine and serotonin), in rat striatum and hippocampus were studied. The plasma concentrations of PHT associated with therapeutic activity did not affect striatal and hippocampal extracellular levels of monoamines, whereas supratherapeutic concentrations of PHT decreased striatal and hippocampal extracellular levels of monoamines, in a concentration dependent manner. Toxic concentrations of PHT produced generalized seizures 'paradoxical intoxication' and an initial drastic decrease in striatal and hippocampal extracellular levels of monoamines before seizure onset, whereas the extracellular monoamines levels increased after seizures. In addition, the therapeutic concentrations of PHT did not affect monoamine turnover, whereas supratherapeutic concentrations of PHT inhibited monoamine turnover. These results suggest that monoaminergic transmission may not be involved in the antiepileptic mechanism of action of PHT, and that dysfunction of monoaminergic transmission can produce generalized tonic-clonic convulsions. Thus, the present study suggests that 'Paradoxical Intoxication' induced by toxic concentrations of PHT, at least partially, can be mediated by hypo-monoaminergic function in the brain.

Effect of plaunotol on gastric injury induced by ischaemia-reperfusion in rats

Plaunatol, an anti-ulcer drug, increases prostaglandin content in gastric tissue but its effect on radical-mediated gastric damage or activity against reactive oxygen species is unknown. We examined the effects of oral administration of plaunotol (Kelnac) on the acute gastric mucosal lesion and its progression to ulcer lesion induced by ischaemia-reperfusion in rats. Plaunotol (30 and 100 mg kg-1, 15 min before ischaemia) significantly reduced the total erosion area observed immediately after ischaemia-reperfusion. When plaunotol (30 and 100 mg kg-1, once a day) was administrated orally 60 min after reperfusion, it prevented the progression from erosion to ulcer. At 72 h after ischaemia-reperfusion, the total area of ulcers lesions was significantly reduced compared with that without plaunotol administration. Furthermore, treatment with plaunotol (100 mg kg-1) significantly increased prostaglandin E2 content in gastric tissues of both acute gastric mucosal lesion and gastric ulcer lesion. In in-vitro experiments, plaunotol (1-3 mg mL-1) reduced the superoxide radicals generated by leucocytes, but not by xanthine oxidase. These results indicate that plaunotol has protective effects on both the onset of acute gastric mucosal injury and its progression to ulcer lesion induced by ischaemia-reperfusion. Both effects of plaunotol on increase in prostaglandin content in gastric tissues and inhibition of superoxide radical from leucocytes may play important roles on the protection against gastric mucosal injury.

Effects of alkaloids from Aconitum yesoense var. macroyesoense on cutaneous blood flow in mice

Nine alkaloid constituents in the root of Aconitum yesoense var. macroyesoense, as well as three acetylated derivatives, were examined for their peripheral vaso-activities by measuring laser-flowmetrically the cutaneous blood flow in the hind foot of mice after intravenous administration. The major constitutive delcosine (1), 14-acetyldelcosine (2) and lucidusculine (3), respectively, had little or very mild vaso-activity. Kobusine (4) and pseudokobusine (5) and three minor constituents, luciculine (6), 1-acetylluciculine (7) and dehydroluciculine (8), together exhibited a rapid increase in blood flow reaching a peak with a magnitude almost equal to that produced by hydralazine, when administered intravenously at the same dosage level of 20 mg/kg. Among them, 4 was characterized by successive reversal of the increase to a decrease in blood flow, while 7 produced a flow with a more delayed peak time. Dehydrolucidusculine (9) exhibited a transient decrease in blood flow prior to occurrence of the increase, as did papaverine. Consequently, it is assumed that the alkaloids, especially those of the C20-diterpenoid type, in the root of this Aconitum plant have peripherally vaso-dilating activities to varying degrees in mice, probably due to their direct action on the cutaneous microvasculature in a similar fashion to that shown by hydralazine. The laser blood flowmetric method would be useful as an in vivo means of qualitative as well as quantitative screening of chemically modified derivatives of peripherally vasoactive agents in mice.

A novel allosteric potentiator of AMPA receptors: 4--2-(phenylsulfonylamino)ethylthio--2,6-difluoro-phenoxyaceta mide

We report that a novel sulfonylamino compound, 4-[2-(phenylsulfonylamino)ethylthio]-2,6-difluoro-phenoxyacetam ide (PEPA), selectively potentiates glutamate receptors of the AMPA subtype. PEPA (1-200 microM) dose dependently potentiated glutamate-evoked currents in Xenopus oocytes expressing AMPA (GluRA-GluRD), but not kainate (GluR6 and GluR6+KA2) or NMDA (zeta1 + epsilon1-epsilon4), receptor subunits. PEPA was effective at micromolar concentrations and, in contrast to the action of cyclothiazide, preferentially modulated AMPA receptor flop isoforms. At 200 microM, PEPA potentiated glutamate responses by 50-fold in oocytes expressing GluRCflop (EC50 approximately 50 microM) versus only threefold for GluRCflip; a similar preference for flop isoforms was observed for other AMPA receptor subunits. Dose-response analysis for GluRCflop revealed that 100 microM PEPA produced a sevenfold increase in AMPA receptor affinity for glutamate. PEPA produced considerably weaker potentiation of kainate-evoked than glutamate-evoked currents, suggesting modulation of the process of receptor desensitization. In human embryonic kidney 293 cells transfected with AMPA receptor subunits, PEPA either abolished or markedly slowed the rate of onset of desensitization and potentiated steady-state equilibrium currents evoked by glutamate with subunit (GluRC >/= GluRD > GluRA) and splice-variant (flop > flip) selectivity similar to that observed in oocytes. Our results show that PEPA is a novel, flop-preferring allosteric modulator of AMPA receptor desensitization at least 100 times more potent than aniracetam.

Comparison of the DNA content of megakaryocytes identified immunologically with that identified morphologically

We devised a new microfluorometric method for determining the ploidy of megakaryocytes identified immunologically in bone marrow smears. The smears were immunostained by incubation with mouse monoclonal anti-glycoproteins (GP) IIb antibodies, followed by fluorescein isothiocyanate-conjugated goat antimouse IgG antibodies. They were then stained with 4',6-diamidino-2-phenylindole (DAPI). Megakaryocytes were identified by their GPIIb immunofluorescence using a microfluorometer and, after the filters were changed, their DNA content was assayed by measuring the intensity of DAPI fluorescence. This intensity was shown to be proportional to the DNA content when the aperture of the objective lens was reduced. We compared these results with those obtained when megakaryocytes were identified morphologically, using DAPI staining after Wright-Giemsa destaining. In all 12 normal controls, the ploidy peaks were shown to be 16N by both methods, and the mean ploidy detected by the immunological method was only reduced 0.961 times relative to the estimate from the morphological method. In contrast, in eight myelodysplastic syndrome (MDS) patients, the ploidy peaks were either 8N or 4N and the mean was reduced by 0.906 times (P = 0.018). Thus we could immunologically identify small megakaryocytes which we could not identify morphologically. Therefore, this method is useful for measuring megakaryocytic ploidy, especially in the pathological megakaryocytes of MDS patients.

Preventive effect of iganidipine on renal and cerebral injuries in salt-induced hypertension

Iganidipine, a new water-soluble calcium antagonist, was administered at a nonhypotensive dose (NHD) of 0.3 mg/kg/day, a moderate-hypotensive dose (MHD) of 1.0 mg/kg/day, and a sustained-hypotensive dose (SHD) of 3.0 mg/kg/day to Dahl salt-sensitive (Dahl-S) rats fed a high-salt diet for 8 weeks. The effects on survival, and on renal and cerebral injuries, were then examined. Iganidipine completely prevented hypertensive death at the SHD and tended to increase the survival at the NHD and MHD. Iganidipine reduced glomerulosclerosis and renal arterial and tubular injuries in a dose-dependent manner. Iganidipine at the SHD, but not NHD or MHD, improved plasma creatinine, serum urea nitrogen, and glomerular filtration rate. Iganidipine at all doses examined increased the urinary prostaglandin (PG) I2 and PGE2, but not PGF2alpha or thromboxane B2, and decreased plasma angiotensin II (AII) level and renin activity. The renal glomerular, tubular, and arterial injuries were significantly correlated with blood pressure (r = 0.56 to 0.80) and plasma AII level (r = 0.50 to 0.71) but not with urinary prostanoids. Iganidipine also reduced the incidence of cerebral infarction. The infarction area was slightly and significantly correlated with urinary PGI2 (r = 0.42) and PGE2 (r = 0.41) but not with blood pressure or plasma AII. In conclusion, iganidipine prevented renal and cerebral injuries in Dahl-S rats. In addition to the reduced blood pressure, the reduction of plasma AII and the increase of vasodilatory prostanoids may also partially contribute to the renal and cerebral protective effects of iganidipine.

An in-frame deletion in peripheral myelin protein-22 gene causes hypomyelination and cell death of the Schwann cells in the new Trembler mutant mice

Cloning and sequencing of the peripheral myelin protein-22 cDNA and genomic DNA from newly found Trembler mice revealed an in-frame deletion including exon IV which codes for the second (TM2) and a part of third (TM3) transmembrane domain of peripheral myelin protein-22. This mutation was distinct from those in both other allelic Trembler and Trembler-J mice, which carry point mutations within the putative transmembrane spanning regions of peripheral myelin protein-22. Inheritance was autosomal dominant. The affected mice revealed an abnormal gait, which appeared at 15-20 days of age, followed by motor and sensory ataxia, which remained throughout life. Most of the affected mice could survive more than one year. One of the most notable pathological phenotypes was a giant vacuolar formation in the sciatic nerve of homozygotes. They vary in size within the cytoplasm of Schwann cells, which failed to assemble myelin at any ages studied. Heterozygotes showed normal myelination during the early postnatal stages, followed by a segmental demyelination at an advanced stage. Vacuolar formation was not so frequent as in the homozygotes. These results suggest that the missing of transmembrane spanning region (TM2 and TM3) of peripheral myelin protein-22 may disturb a dual biological function of peripheral myelin protein-22, leading to a dysmyelination of axons and to a vacuolar formation within the cytoplasm of the Schwann cells. The latter phenotype is discussed in conjunction with the disruption of an intracellular transport system and subsequent cell death.

[Epstein-Barr virus-infected T-cell malignancy in an adult patient with Behçet's disease-like symptoms]

A 20-year-old woman was hospitalized on November 11, 1994 with Behçet's disease-like symptoms (fever, genital ulcer and aphtha in the oral cavity). Bilateral cervical lymph node swelling was also noted and diagnosed as lymphadenitis on biopsy. Chronic active Epstein-Barr virus infection (CAEBV) was diagnosed based on the high titer of antibodies to the EBV capsid antigen, early antigen, and nuclear antigen. She was treated with prednisolone and acyclovir and all symptoms improved. However, ten months after onset of symptoms, T-cell malignancy was diagnosed on bone marrow aspiration, which revealed 34.9% blast cells that had rearrangement of TCR-beta. She died on May 8, 1995, despite anticancer therapy. In analyzing the blast cells, the monoclonal junctional DNA structure of the EBV terminal repeat was analyzed by Southern blotting and provided definitive evidence for the monoclonality of EBV-infected T cells. These findings strongly suggest that EBV plays a pathogenic role in T-cell malignancy. EBV-infected T-cell malignancy, such as this case, is very rare in Japan, especially in adult.

Structure and functional expression of the cloned mouse neuronal high-affinity glutamate transporter

A cDNA encoding a neuron-specific glutamate transporter was isolated from mouse cerebellum and characterized. Expression of this cDNA in HEK293 cells induced high-affinity uptake of L-glutamate that was dependent on external Na+. The deduced amino-acid sequence of the cDNA shares 96% identity with its human homologue. Northern blot analysis of mouse tissues revealed that the mRNA of this transporter is specific to the brain. In situ hybridization in mouse brain sections showed that the mRNA is expressed densely and selectively in cell bodies of Purkinje cells.

Prognosis and clinical features of intractable epilepsy: a prospective study

Of the epileptic patients who were treated for > or = 5 years until the end of 1990 and had more than four seizures in 1990, 63 patients had been treated without interruption until the end of 1995. We analyzed their clinical courses from 1990 to 1995 prospectively. More than half the subjects were diagnosed with temporal lobe epilepsy. Twenty cases had presumed etiology, and 32 had neuropsychiatric complications. Of the subjects whose seizures were not controlled with conventional antiepileptic drugs (AED), 11 cases demonstrated significant improvement when new AED; that is, lamotrigine, vigabatrin, clobazam, topiramate, tiagabine or CGP33101 were added. However, 10 patients did not respond to new AED. Presumed etiology, neuropsychiatric complications, multiple epileptic foci in EEG and abnormalities on head CT or MRI were characteristics of the patients whose seizures were resistant to new AED.

[Usefulness of 7 day therapy with cefluprenam in the management of respiratory tract infections]

Efficacy and safety of a newer injectable cephalosporin, cefluprenam (CFLP) on cases with bacterial pneumonia and chronic respiratory tract infections were evaluated at a dose of 1g (potency), d.i.d for 7 days. 1. Of 130 cases in total, 116 cases were enrolled for the clinical efficacy evaluation. The efficacy rate (excellent and good responses) was 94.8% (110/116). The efficacy rate was 93.8% (60/64) for cases with bacterial pneumonia, and 96.2% (50/52) for cases with chronic respiratory tract infections. The recurrence was noted in 1.2% (1/82). The bacteriological response rate was 100.0% (32/32) for gram positive cocci, 93.8% (15/16) for gram negative rods and 97.9% (47/48) in total. 2. Adverse drug reactions were noted in 3.9% (5/129), consisting of 2 cases with skin rash, 1 case with drug fever, 1 case with skin rash and skin itching and 1 case with drug fever and headache. The abnormal laboratory changes were noted in 23.6% (30/127), mainly containing the elevation in GPT and GOT, and eosinophylia. The safety rate (no problem evaluation) was 74.8% (95/127). 3. The usefulness rate (very useful and useful evaluations) was 93.1% (108/116). As suggested by the evaluation on the secondary endpoint in the phase III comparative studies with both bacterial pneumonia and chronic respiratory tract infections, it was confirmed that the 7 day therapy of CFLP was promising for treatment of moderate bacterial pneumonia and chronic respiratory tract infections, because the high clinical efficacy was obtained and also the incidence of allergic reactions with CFLP was almost the same as that of ceftazidime (CAZ) evaluated highly safe. Based on these results, it was concluded that CFLP was useful in the management of moderate respiratory tract infections and also the recommended therapeutic period with CFLP was within 7 days.

Cloning and expression of the neuromedin B receptor and the third subtype of bombesin receptor genes in the mouse

We cloned the genes for the mouse homologue of the neuromedin B receptor (NMB-R) and the bombesin receptor subtype 3 (BRS-3). Both receptor genes consist of three exons with well-conserved intron-exon borders. Although the NMB-R gene spans more than 10 kb, the BRS-3 gene spans only about 4 kb. Comparison of the mouse and human receptor sequences indicates 90% (NMB-R) and 85% (BRS-3) sequence homology at the amino-acid level. In the adult mouse, the NMB-R mRNA is expressed in the brain, testis, esophagus, intestine and uterus, whereas the BRS-3 mRNA is expressed predominantly in the brain. In the brain, the NMB-R gene expression is prominent in the thalamic and olfactory regions, and the BRS-3 gene is expressed particularly in the hypothalamic region. In mouse testis, the NMB-R gene expression is prominent, and the expression of BRS-3 mRNA is barely detected. In contrast, BRS-3 has been shown to be expressed in rat testis and guinea-pig uterus, therefore it is possible that a different subtype of the bombesin receptor mediates the same response in different species. Together with the mouse GRP-R gene cloned previously, cloning of the mouse NMB-R and BRS-3 genes permits comparison of function and structure of the three bombesin receptor subtypes in the mouse.

Cigarette smoking and solvent use among Japanese adolescents

To examine the relationship between cigarette smoking and solvent use among Japanese adolescents, epidemiologic data from a survey of 4433 junior high school students were analyzed. For both males and females, the frequency of cigarette smoking was positively associated with curiosity about solvent use, the perception of closeness to solvent users and the lifetime and past-year prevalence rates of solvent use. On the other hand, the frequency of smoking was negatively associated with the endorsement of the current Japanese law which maintains the illegality of solvent use. These results are reported for the first time from epidemiologic-based data among early adolescents in Japan. Although correlational, they suggest the role of cigarette smoking for Japanese adolescents in the initiation of other illicit drug use in these age groups.

Loss of the tumor suppressor p53 gene at the liver cirrhosis stage in Japanese patients with hepatocellular carcinoma

The incidence of p53 gene aberrations is reported to be about 20-50% in hepatocellular carcinomas (HCCs). In most cases, HCC is clinically preceded by liver cirrhosis, but the genetic changes in cirrhosis are not known well. Therefore, we studied the loss of heterozygosity (LOH) of the p53 gene in cirrhotic and neoplastic foci in the livers of patients with HCC. To assess the relationship between the LOH status of the p53 gene in the liver cirrhosis stage and that in HCC, we analyzed the samples microdissected from paraffin-embedded tissues using the polymerase-chain-reaction-based assay. We studied 18 patients with HCC. Fourteen of the 18 cases showed constitutional heterozygosity for the microsatellite markers. In 8 (57%) of the 14 informative cases, LOH was detected in primary HCCs. Among these 8 doubly informative (informative and LOH positive in primary HCC) cases, 5 cases (63%) showed LOH in liver cirrhosis lesions. The pattern of p53 allelic loss in the cirrhotic foci was identical with that in the corresponding tumor. The remaining 6 cases without LOH of the p53 gene in HCC showed on p53 loss in any cirrhotic foci. LOH of the p53 gene may occur before the development of HCC.

Radioiodinated alpha-p-iodophenyl-N-tert-butylnitrone as a radical detecting agent in vivo

For in vivo detection of unstable radical species, a novel radioiodinated radical trapping agent, alpha-p-iodophenyl-N-tert-butylnitrone (IPBN), was designed based on the plausible characteristics of alpha-p-hydroxy-m-iodophenyl-N-tert-butylnitrone (HIPBN). Both compounds are iodinated analogs of alpha-phenyl-N-tert-butylnitrone (PBN), but the latter showed low stability in vivo. The present compound IPBN was easily prepared and labeled with radioiodine. It showed very stable characteristics in vitro as well as in vivo, but was easily metabolized and retained at sites of superoxide production.

Epilepsy and exacerbation of brain injury in mice lacking the glutamate transporter GLT-1

Extracellular levels of the excitatory neurotransmitter glutamate in the nervous system are maintained by transporters that actively remove glutamate from the extracellular space. Homozygous mice deficient in GLT-1, a widely distributed astrocytic glutamate transporter, show lethal spontaneous seizures and increased susceptibility to acute cortical injury. These effects can be attributed to elevated levels of residual glutamate in the brains of these mice.

Substances in the aqueous fraction of cigarette smoke inhibit lipid peroxidation in synaptosomes of rat cerebral cortex

The effects of water-soluble substances in cigarette smoke on lipid peroxidation were investigated using nerve terminals prepared from the rat cerebral cortex. The prepared smoke-substances significantly reduced the spontaneous increase in thiobarbituric acid-reactive substances in synaptosomes in a dilution factor-dependent manner. Furthermore, the aqueous extract also inhibited the elevation of lipid peroxidation induced by 2,2'-azobis (2-amidinopropane) dihydrochloride, a peroxyl radical generator. Smoke-substances scavenged superoxide radicals generated from stimulated human leukocytes and from the xanthine/xanthine oxidase system. These effects were not mimicked by nicotine. The antioxidant effects of smoke-substances were preserved for several days at 5 degrees or -80 degrees C. The results suggest that the smoke-substances may possess long half-lives and scavenge the radicals which cause lipid-peroxidation in synaptosome membranes.

Incidence of dogs possessing red blood cells with high K in Japan and East Asia

The phenotype of high K (HK) red blood cells, which is an autosomal recessive, was found in dog groups from 10 of 13 breeds or populations in Japan. The incidence of HK was 26 to 38% in the San'in-Shiba, Shinshu-Shiba and Akita breeds, and the gene frequencies of HK ranged from 0.513 to 0.612. The highest incidence (42%) was found in the Jindo breed from Korea, and the gene frequency was 0.652. Two other groups from Korea also possessed this HK variation. However, although HK cells were not found in dogs from Taiwan, Indonesia, Mongolia and Sakhalin, Russia, the HK phenotype is clearly distributed now throughout Japan and Korea.