Biomedical subjects

F Suzuki

Publications and source records attributed to F Suzuki.

At least 55 records · Page 3Linked to original sources

PubMed2000

Nine polymorphisms of angiotensinogen gene in the susceptibility to essential hypertension.

Even if the importance of angiotensinogen (AGT) gene has been known in gene targeting animals and humans genetic studies, its precise mechanism and the interaction among AGT gene variants, plasma AGT concentration and risk for hypertension remain uncertain. We examined whether AGT gene variants predispose to hypertension via an increase of plasma AGT concentration. Plasma AGT concentration was estimated from plasma angiotensin I which was cleaved by an excess amount of human renin and measured by RIA. Using 9 AGT gene variants which included new polymorphisms (G-152A and T+31C), we examined the association with hypertension and with plasma concentration by a case-control study. Haplotype analysis revealed that G-6A, T+31C and M235T polymorphisms were in absolute linkage disequilibrium and were associated with hypertension but not with plasma AGT level. On the other hand, -1074t;T235 haplotype was associated with an increase of AGT level but not with hypertension. In the haplotype analysis, only H3 haplotype frequency, which contained G-6, T+31 and M235 alleles, was significantly increased in normotensive subjects, suggesting that this haplotype is associated with a hypotensive effect. According to combined haplotype analysis of diallele and microsatellite markers, it remains a possibility that M235T, T+31C, G-6A, A-20C and G-1074T polymorphisms may play an important role in increased risk for essential hypertension. Our results suggest that the positive association between AGT polymorphism and hypertension is not simply explained by an increase of plasma AGT concentration.

Alleles↗

PubMed2000

A pathogenic role of Th2 responses on the severity of encephalomyelitis induced in mice by herpes simplex virus type 2 infection.

A pathogenic role of Th2 cells and their cytokine products (IL-4 and IL-10, Th2 cytokines) on the development of herpes simplex myelitis (HSM) was studied in mice exposed to footpad injection of herpes simplex virus type 2 (HSV-2). Morbidity and mortality of mice with HSM (HSM mice) increased when they were treated with a mixture of Th2 cytokines. Additionally, survival rates of HSM mice increased when they were treated with a mixture of mAbs for Th2 cytokines. As compared with HSM mice treated with saline, the growth of HSV-2 in spinal cords of HSM mice treated with the mixture of Th2 cytokines increased. Th2 cells (myelitis-associated Th2 cells, MTh2 cells) were demonstrated among cerebrospinal fluid cells from HSM mice. After the stimulation with HSV-2 antigen (Ag), MTh2 cells from HSM mice previously treated with the mixture of Th2 cytokines produced enhanced amounts of Th2 cytokines into their culture fluids, as compared with the amount of Th2 cytokines produced by MTh2 cells. Th2 cells were also demonstrated in mononuclear cells from spleens of HSM mice. When compared with HSM mice inoculated with splenic CD4(+) T cells from normal mice, morbidity and mortality of HSM mice inoculated with MTh2 cells markedly increased. These results indicated that the severity of HSM induced in mice by footpad injection of HSV-2 was influenced by MTh2 cells or Th2 cytokines released from these MTh2 cells. Th2 responses manifested in mice by HSV-2 infection may act as a pathogenic enhancer of HSM severities.

Adoptive Transfer↗

PubMed2000

Incidence of primary cholangiocellular carcinoma of the liver in japanese patients with hepatitis C virus-related cirrhosis.

BACKGROUND: Hepatitis C virus (HCV) infection is a major risk factor for the development of hepatocellular carcinoma. However, the risk factors for primary cholangiocellular carcinoma of the liver (PCC-L) have not been fully investigated. The authors determined the incidence of PCC-L in patients with HCV-related cirrhosis. METHODS: Between 1980 and 1997, the authors prospectively studied 600 consecutive patients for the appearance of PCC-L; these patients were positive for HCV and later developed cirrhosis. The follow-up period ranged from 0 to 18.5 years (median, 7.2 years). RESULTS: During the observation period, PCC-L developed in 14 patients (2.3%). Among these, 11 (1.8%) had cholangiocellular carcinomas and the other 3 (0.5%) had a combined type of hepatocellular and cholangiocellular carcinoma. Within the same period, hepatocellular carcinoma (HCC) developed in 206 patients (34.3%). The cumulative rates of newly diagnosed PCC-L were 1.6% at 5 years and 3.5% at 10 years, which was about 1000 times higher than the estimated incidence of PCC-L in the general population of Japan. PCC-L was treated by surgical resection in 3 patients who survived for > 3 years. However, the other 11 patients received palliative therapy or chemotherapy. The survival rates among PCC-L patients were 39.3%, 23. 6%, and 16.5% at the end of 1, 3, and 5 years, respectively, and were significantly lower than those of HCC (P = 0.0001). CONCLUSIONS: The results of this study show a relatively high incidence of PCC-L in patients with HCV-related cirrhosis, and also show that this type of liver cancer is associated with a relatively poor prognosis. These results indicate that HCV-related cirrhosis is a major risk factor for PCC-L in Japanese patients.

Adult↗

PubMed2000

Cloning of rabbit alpha(1b)-adrenoceptor and pharmacological comparison of alpha(1a)-, alpha(1b)- and alpha(1d)-adrenoceptors in rabbit.

We have isolated a cDNA clone of the rabbit alpha(1b)-adrenoceptor which has an open reading frame of 1557 nucleotides encoding a protein of 518 amino acids. The sequence shows higher identity to those of hamster, human, and rat alpha(1b)-adrenoceptors than to those of rabbit alpha(1a)- and alpha(1d)-adrenoceptors. The pharmacological binding properties of this clone expressed in Cos-7 cells showed a characteristic profile as alpha(1b)-adrenoceptor; high affinity for prazosin (pK(i)=10.3), relatively high affinity for tamsulosin (9.5) and low affinity for (-)-(R)-1-(3-hydroxypropyl)-5-[2-[[2-[2-(2,2, 2-trifluoroethoxy)phenoxy]ethyl]amino]propyl]indoline-7-carboxamid e (KMD3213) (8.5), 2-(2,6-dimethoxy-phenoxyethyl)-aminomethyl-1, 4-benzodioxane hydrochloride (WB4101) (8.7), and 8-[2-[4-(2-methoxy-phenyl)-L-piperazinyl]-8-azaspiro[4,5]decane-7, 9-dione dihydrochloride (BMY7378) (7.3). We have compared the levels of mRNA expression of three alpha(1)-adrenoceptor subtypes in rabbit tissues using the competitive reverse transcription/polymerase chain reaction (RT/PCR) assay. In most rabbit tissues except heart, alpha(1a)-adrenoceptor mRNA was expressed 10 folds more than the other two subtypes. However, binding experiments with [3H]prazosin and [3H]KMD3213 in rabbit tissues revealed a poor relationship between binding density and mRNA level. Especially, alpha(1b) binding sites were exclusively predominant in spleen, whereas the alpha(1b) subtype was minor at the mRNA level. These results indicate a high identity of structural and pharmacological profiles of three distinct alpha(1)-adrenoceptor subtypes between rabbit and other species, but there are species differences in their distribution.

Adrenergic alpha-Antagonists↗

PubMed2000

Molecular cloning of mouse thioredoxin reductases.

We screened clones for thioredoxin reductase genes with a degenerate PCR-based strategy and have isolated two novel cDNA clones from a mouse thymocyte cDNA library. These encode two distinct thioredoxin reductases (TrxR1 and TrxR2) with 499 and 527 amino acid (aa) residues and calculated molecular masses of 54.5 kDa and 56.8 kDa respectively. These proteins share 90% and 50% aa sequence identity with those of previously cloned human TrxR, containing the redox-active cysteines, FAD binding domain, and the selenocysteine (SeCys) insertion sequence, which is composed of a putative stem-loop sequence located in the 3'-untranslated region (UTR). TrxR2 showing less homology to human TrxR has a mitochondrial translocation signal and a mitochondrial prepeptide protease cleavage site in the N-terminal domain. Transient expression experiments of each gene as fusion proteins with Xpress-tagged protein in NIH 3T3 cells indicated that TrxR1 was localized in the nucleus and cytoplasm and TrxR2 in the mitochondria. Furthermore, we mapped the TrxR1 gene to chromosome 10 (placed 1.71 cR from D10Mit42, lod>3.0) and the TrxR2 gene to chromosome 16 (placed 22.56 cR from D16Mit34, lod>3.0). Thus, the mouse has at least two distinct nuclear genes for TrxR that have different translocation sites in the cell.

3T3 Cells↗

PubMed2000

The dominant role of the prosegment of prorenin in determining the rate of activation by acid or trypsin: studies with molecular chimeras.

Human prorenin activation by acid or trypsin is faster than rat prorenin by two orders of magnitude. No plausible mechanism exists to explain the difference. Two chimeric mutant prorenins were produced in CHO cells. A chimera, hPro/rRen, composed of human prorenin prosegment and rat active renin segment, was activated as fast as wild-type human prorenin at pH 3.3 and 25 degrees C or by trypsin (1 microg/ml). The other chimera, rPro/hRen, composed of rat prorenin prosegment and human active renin segment, was activated as slowly as wild-type rat prorenin at pH 3.3 and 25 degrees C or by trypsin (50 microg/ml). These results indicate that the rate of activation of prorenin is predominantly determined by the N-terminal pro-sequence. Plausible mechanisms are discussed.

Amino Acid Sequence↗

PubMed2000

Glycyrrhizin improves the resistance of MAIDS mice to opportunistic infection of Candida albicans through the modulation of MAIDS-associated type 2 T cell responses.

Compared with normal mice, MAIDS mice (mice infected with LP-BM5 murine leukemia virus) exhibited an increase up to 100 times greater in susceptibility to infection with Candida albicans. The impaired resistance of MAIDS mice to the infection was recovered to levels observed in normal mice by the administration of glycyrrhizin (GR), an active component of licorice roots. MAIDS mice inoculated with CD4(+) T cells from GR-treated mice were also resistant to C. albicans infection. Normal mice inoculated with CD4(+) T helper type 2 cells (Th2 cells) from MAIDS mice were susceptible to C. albicans infection at the same levels shown in MAIDS mice. The susceptibility of normal mice inoculated with type 2 T cells was reversible by (i) administration of GR and (ii) inoculation of CD4(+) T cells from GR-treated mice and injection of a mixture of mAbs targeted against type 2 cytokines (IL-4 and IL-10). Type 2 cytokines were not detected in sera of MAIDS mice inoculated with CD4(+) T cells from GR-treated mice, while they were present in sera of MAIDS mice treated with saline. These results suggest that, by inducing CD4(+) T cells which suppress type 2 cytokine production by MAIDS-associated Th2 cells, GR improves the resistance of MAIDS mice to C. albicans infection.

AIDS-Related Opportunistic Infections↗

PubMed2000

Evaluation of iodinated and brominated [11C]styrylxanthine derivatives as in vivo radioligands mapping adenosine A2A receptor in the central nervous system.

In vivo assessment of the adenosine A2A receptors localized in the striatum by PET or SPECT offers us a new diagnostic tool for neurological disorders. In the present study, we evaluated the potential of iodinated and brominated styrylxanthine derivatives labeled with 11C as an in vivo probe. [7-Methyl-11C]-(E)-3,7-dimethyl-8-(3-iodostyryl)-1-propargylxan thine ([11C]IS-DMPX) and [7-methyl-11C]-(E)-8-(3-bromostyryl)-3,7-dimethyl-1-propargylxa nthine ([11C]BS-DMPX) were prepared by the 11C-methylation of corresponding 7-demethyl derivatives. An in vitro membrane binding study showed a high affinity (Ki values) of the two ligands for A2A receptor: 8.9 nM for IS-DMPX and 7.7 nM for BS-DMPX, and a high A2A/A1 selectivity: > 1100 for IS-DMPX and 300 for BS-DMPX. In mice, [11C]IS-DMPX and [11C]BS-DMPX were taken up slightly more in the striatum than in the reference regions such as the cortex and cerebellum. The uptake ratios of striatum to cortex and striatum to cerebellum gradually increased but were very small: 1.6-1.7 for the striatum-to-cortex ratio and 1.2 for the striatum-to-cerebellum ratio at 60 min postinjection. The uptake by these three regions was reduced by co-injection of an excess amount of carrier or an A2A antagonist KF17837, but not by an A1 antagonist KF15372. The blocking effects in the three regions were greater for [11C]BS-DMPX (32-57%) than for [11C]IS-DMPX (6-29%). Ex vivo autoradiography confirmed that the two ligands were slightly concentrated in the striatum. [11C]BS-DMPX showed more selective affinity for adenosine A2A receptors than [11C]IS-DMPX, but these results have shown that the two tracers were not suitable as in vivo ligands because of low selectivity for the striatal A2A receptors and a high nonspecific binding.

Animals↗

PubMed2000

Search for PET probes for imaging the globus pallidus studied with rat brain ex vivo autoradiography.

We have evaluated the feasibility of using four positron emission tomography (PET) tracers for imaging the globus pallidus by ex vivo autoradiography in rats. The tracers investigated were [11C]KF18446, [11C]SCH 23390 and [11C]raclopride for mapping adenosine A2A, dopamine D1 and dopamine D2 receptors, respectively, and [18F]FDG. The highest uptake by the globus pallidus was found for [11C]SCH 23390, followed by [18F]FDG, [11C]KF18446 and [11C]raclopride. The receptor-specific uptake by the globus pallidus was observed in [11C]KF18446 and [11C]SCH 23390, but not in [11C]raclopride. Uptake ratios of globus pallidus to the striatum for [18F]FDG and [11C]KF18446 were approximately 0.6, which was twice as large as that for [11C]SCH 23390. In a rat model of degeneration of striatopallidal gamma-aminobutyric acid-ergic-enkephalin neurons induced by intrastriatal injection of quinolinic acid, the uptake of [11C]KF18446 by the striatum and globus pallidus was remarkably reduced. To prove the visualization of the globus pallidus by PET with [18F]FDG and [11C]KF18446, PET-MRI registration technique and advances in PET technologies providing high-resolution PET scanner will be required. The metabolic activity of the globus pallidus could then be measured by PET with [18F]FDG, and [11C]KF18446 may be a candidate tracer for imaging the pallidal terminals projecting from the striatum.

Animals↗

PubMed2000

Further characterization of a CNS adenosine A2a receptor ligand [11C]KF18446 with in vitro autoradiography and in vivo tissue uptake.

PET assessment of the adenosine A2a receptors localized in the striatum offers us a potential new diagnostic tool for neurological disorders. In the present study, we carried out in vitro receptor autoradiography of a newly developed PET ligand [11C]KF18446 ([7-methyl-11C]-(E)-8-(3,4,5-trimethoxystyryl)-1,3,7-trimethylxanthin e) with rat brain sections. [11C]KF18446 showed a high striatum/cortex binding ratio (5.0) and low nonspecific binding (<10%), suggesting that [11C]KF18446 has characteristics comparable or slightly superior to [3H]CGS 21680 or [3H]SCH 58261, which are currently available representative A2a receptor ligands. Scatchard analysis indicated a Kd of 9.8 nM and a Bmax of 170 fmol/mm3 tissue in the striatum and a Kd of 16.4 nM and a Bmax of 33 fmol/mm3 tissue in the cortex. Seven xanthine-type and four nonxanthine-type adenosine receptor ligands with an affinity for the adenosine A2a receptors significantly reduced the in vitro binding of [11C]KF18446 to the brain section. The blocking effects were much stronger in the striatum than in the cortex, but did not necessarily parallel their affinity. On the other hand, four xanthine-type ligands and one nonxanthine-type ligand (SCH 58261) of the 11 ligands studied reduced the in vivo uptake of [11C]KF18446 in mice, but other ligands, including A1-selective and nonselective ligands and three nonxanthine-type A2a-selective antagonists did not. We conclude that [11C]KF18446 is a promising adenosine A2a receptor ligand for PET study.

Animals↗

PubMed2000

Pre-existing histological type and developmental mechanism of mucinous noncystic carcinoma of pancreas.

Eleven cases with mucinous noncystic carcinoma (MC) of the pancreas were studied by histology and mucin immunohistochemistry, to elucidate the mechanism, or route of development, and pre-existing histological type of MC of the pancreas. These MCs were observed in close approximation to, or surrounding, intraductal papillary-mucinous carcinomas (IPMCs), and were centrally situated among ductal adenocarcinomas (DAs). Hence, the 11 cases originated from 8 IPMCs and 3 DAs. The mechanism and routes to MC were divided into four types as follows: IPMC directly invaded the stroma (4 cases), over-production of mucin in IPMC expanded the branches of the pancreatic duct possibly resulting in rupture (3 cases), DA underwent extreme mucinous degeneration (3 cases), and a recurrent form, as MC, at the surgical stump of IPMC (one case). The outcomes of MC cases with IPMC had variable survival rates, while those from DA had short durations. MUC immunoreactivity in MC was divided into three categories; anti-MUC1-positive only (2 IPMCs, 2 DAs), mixed anti-MUC1 and anti-MUC2-positive (3 IPMCs, one DA) and anti-MUC-positive only (3 IPMCs). Pre-existing MC histological types included both IPMC and DA. These two pre-existing types of MC involved mucin overproduction and mucinous degeneration. MUC immunoreactivity in MC revealed three patterns, which may be related to variable outcomes.

Adenocarcinoma↗

PubMed2000

Fluctuation patterns of HCV-RNA serum level in patients with chronic hepatitis C.

The serum level of hepatitis C virus (HCV)-RNA is clinically important as a predictor of the response to interferon (IFN) therapy in patients with chronic hepatitis C. If serum HCV-RNA levels fluctuate during follow-up, and IFN therapy is begun at the time of a low HCV-RNA level, the IFN therapy may be more effective. We evaluated the fluctuation of HCV-RNA serum levels for 2 years in 212 patients with chronic hepatitis C, untreated with IFN who had HCV genotype 1b and an HCV-RNA level of 10 Meq/ml or more at first consultation. The HCV-RNA level was measured monthly for 2 years with an HCV branched DNA probe assay (b DNA probe assay). We classified HCV-RNA patterns into three types by the ratio of maximum HCV-RNA level (a) to minimum HCV-RNA level (b). In pattern 1 (constant type, 151 patients; 71.2%) the a/ b ratio was 1-5. In pattern 2 (slight fluctuation type, 46 patients; 21.7%) the a/b ratio was 5-10. In pattern 3 (severe fluctuation type, 15 patients; 7.1%), the a/b ratio was 10 or more. Next, we evaluated the factors associated with the three patterns. Acute exacerbation of chronic hepatitis was regarded as an increase in serum alanine aminotransferase (ALT) level to more than 250 IU/l. The incidence of acute exacerbation for a 2-year follow-up was 13.9% (21/151) in pattern 1, 19.6% (9/46) in pattern 2, and 53.3% (8/15) in pattern 3. Multivariate analysis showed that acute exacerbation was the most important factor in the manifestation pattern 3. In conclusion, we found that: (1) about 70% of patients had a constant HCV-RNA levels for 2 years. (2) A few patients had severe fluctuation of serum HCV-RNA level after acute exacerbation of chronic hepatitis.

Adult↗

PubMed2000

Hepatic vascular side effects of styrene maleic acid neocarzinostatin in the treatment of hepatocellular carcinoma.

Styrene-maleic acid neocarzinostatin (SMANCS) sometimes causes hepatic vascular side effects, including arterial stricture, obstruction, and arterio-portal shunt. A total of 128 intra-arterial SMANCS injection treatments, performed for 89 patients with hepatocellular carcinoma, were analyzed to determine the relationship between angiographic findings and subsequent hepatic vascular injuries. After SMANCS therapy, hepatic arterial stricture or obstruction occurred in 5 patients (5/128; 3.9%), arterio-portal shunting in 12 (12/128; 9.4%), liver shrinkage in 4 (4/128; 3.1%), and cholangitis or biloma in 2 (2/128; 1.6%). Among 23 patients whose plain abdominal X-ray films just after SMANCS injection showed Lipiodol retention in the hepatic artery, 5 patients developed arterial obstruction, 10 developed arterio-portal shunt, and 2, cholangitis or biloma. Among 26 patients with Lipiodol retention in the portal vein, 4 developed hepatic lobe atrophy with aggravation of liver function. Among 3 patients with Lipiodol retention in both the hepatic artery and the portal vein, 1 developed arterio-portal shunt. In 76 treatments without excessive Lipiodol retention, only 1 of the patients developed arterio-portal shunt. Excessive retention of Lipiodol in hepatic vascular beds just after SMANCS therapy was significantly associated with future vascular side effects (22/52 vs 1/76; P < 0.0001). Lipiodol retention in arteries just after SMANCS injection was closely associated with subsequent arterial obstruction or arterio-portal shunt, and Lipiodol retention in the portal vein was related to subsequent hepatic lobe atrophy.

Adult↗

PubMed2000

Increased response rate to interferon therapy after a second course in hepatitis C patients who show relapse after the initial course.

Some patients with chronic hepatitis C become HCV-RNA seronegative during interferon (IFN) therapy. However, about one-half of these patients show a relapse, evident by high serum alanine aminotransferase (ALT) level. In some patients with biochemical relapse, the serum HCV-RNA level becomes low immediately after the ALT relapse. Here, we assessed the changes in serum HCV-RNA level in patients with ALT relapse after IFN therapy, and evaluated the efficacy of a second course of IFN, started at the recovery stage after ALT relapse. Two hundred and seventy-seven patients who showed HCV-RNA seronegativity by reverse transcription nested-polymerase chain reaction (RT nested-PCR) and normalization of ALT during the initial IFN therapy, and had positive HCV-RNA with ALT relapse (> 100 IU/l) within 3 months after completion of the initial IFN course were enrolled in this retrospective study. Two hundred and sixty patients were followed-up without further IFN retreatment after the ALT relapse (group 1), and 17 patients received another 6-month course of IFN after the ALT relapse (group 2). The median level of serum HCV-RNA, determined with a branched DNA probe assay (version 1; Chiron-Dai-ichi Kagaku Tokyo, Japan), in group 1 was 3.1 Meq/ml before IFN therapy, 1.3 Meq/ml at the time point of the ALT peak after the completion of IFN therapy, and 0.7 and 2.6 Meq/ml at 2-4 and 6-8 weeks after the ALT peak, respectively. The serum HCV-RNA level at 2-4 weeks after the ALT peak was lower than that before IFN therapy. The eradication rate of HCV-RNA (complete response; CR) in group 2 (47.1%; 8/17) was significantly higher than that in group 1 (1.5%; 4/260; P < 0.001). In conclusion, our data suggested that: (1) patients who showed biochemical relapse after initial IFN therapy had a significantly lower serum HCV-RNA level at recovery after ALT relapse compared with that before initial IFN therapy. (2) A high response rate was noted after a second course of IFN administered at the recovery stage of the ALT relapse, compared with patients without IFN retreatment.

Adult↗

PubMed2000

Immunohistological study of intervertebral disc herniation of lumbar spine.

In order to observe histological changes in the extruded and sequestrated intervertebral disc, we conducted pathological and immunological examinations of herniated disc materials taken at the time of discectomy. There were 49 disc materials (from 38 men and 10 women [aged 19 to 78 years; average, 36.6 years]). The herniation was classified into four types, based on the intraoperative observations: protrusion (P), subligamentous extrusion (SE), transligamentous extrusion (TE), and sequestration (S). There were 19 P type discs, 3 SE type, 10 TE type, and 17 S type. The surgical specimens were stained with hematoxylin-eosin, as well as immunohistological staining with the labelled streptavidin biotin method, using human T-cell, human B-cell, and human macrophage antibodies. Inflammatory-cell infiltration was observed at the border of the disc. These findings were present in 19 discs (70%) of the 27 discs of TE and S types (10 TE and 17 S types), but were not seen in the 22 discs of P and SE types (19 P and 3 SE types). Immunohistological staining of the area with inflammatory-cell infiltration revealed the presence of T cells and macrophages, which suggested that this cell infiltration originated from T cells and macrophages, and that the spontaneous resorption of the disc may have resulted from the phagocytic activities of these cells.

Adult↗

PubMed2000

Marked anterograde decremental conduction over a rapidly conducting accessory pathway after radiofrequency ablation.

We report on a patient with the Wolff-Parkinson-White syndrome who temporarily exhibited a marked anterograde decremental conduction over a rapidly conducting accessory atrioventricular pathway after successful radiofrequency ablation. By recording the intracardiac electrogram via the ablation catheter placed at the successful ablation site, we were able to exclude the possibility of the occurrence of anterograde decremental conduction in the atrial or ventricular myocardium between the accessory pathway and the recording electrodes.

Catheter Ablation↗

PubMed2000

Long-term increase of GluR2 alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate receptor subunit in the dispersed dentate gyrus after intrahippocampal kainate injection in the mouse.

Intrahippocampal injection of a subtoxic dose of kainate in mice has been shown to induce a dispersion of granule cells of the dentate gyrus, which is a characteristic morphological change often seen in human hippocampal sclerosis. In addition, it has been shown recently that such injections lead to recurrent hippocampal seizures and changes in glucose metabolism, which are reminiscent of temporal lobe epilepsy. Previous reports on human hippocampal sclerosis have shown an increase of the expression of the GluR2 alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate subunits in the dispersed granule cell somata. However, no such changes have been observed so far in animal models of epilepsy with hippocampal sclerosis. In this study, the expression of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate receptor subunits was examined by immunohistochemistry following intrahippocampal injection of kainate in mice and rats. In mice, such injection induced a persistent increase of GluR2 immunoreactivity in the granule cells for up to 180 days. By contrast, GluR1 immunoreactivity was transiently increased during the first four days after the injection and progressively decreased thereafter. By contrast, intrahippocampal injection of kainate in rats did not result in granule cell dispersion and no changes in GluR1 immunoreactivity or GluR2 immunoreactivity were observed. These results show that, in addition to morphological, clinical and metabolical similarities, intrahippocampal injection of kainate results in a persistent increase of GluR2 associated with granule cell dispersion, as in human hippocampal sclerosis. These data suggest the existence of common mechanisms between granule cell dispersion and regulation of GluR2 subunits associated with hippocampal sclerosis.

Animals↗

PubMed2000

A PET study of adenosine A1 receptor in anesthetized monkey brain.

We demonstrated the distribution of adenosine A1 receptors in the anesthetized monkey brain with positron emission tomography (PET) using [(11)C]KF15372 ([1-propyl-(11)C]8-dicyclopropylmethyl-1, 3-dipropylxanthine). [(11)C]KF15372 was injected intravenously. The regional standardized uptake values and the distribution volume were calculated. We also investigated the effect of carrier on the uptake and regional brain distribution of [(11)C]KF15372. The use of [(11)C]KF15372 with dynamic PET scanning could be an appropriate method to analyze the regional binding potential of adenosine A1 receptors in living brain.

Anesthesia↗