De novo mutations of voltage-gated sodium channel alphaII gene SCN2A in intractable epilepsies.

BACKGROUND: Mutations of voltage-gated sodium channel alpha(II) gene, SCN2A, have been described in a wide spectrum of epilepsies. While inherited SCN2A mutations have been identified in multiple mild epilepsy cases, a de novo SCN2A-R102X mutation, which we previously reported in a patient with sporadic intractable childhood localization-related epilepsy, remains unique. To validate the involvement of de novo SCN2A mutations in the etiology of intractable epilepsies, we sought to identify additional instances. METHODS: We performed mutational analyses on SCN2A in 116 patients with severe myoclonic epilepsy in infancy, infantile spasms, and other types of intractable childhood partial and generalized epilepsies and did whole-cell patch-clamp recordings on Na(v)1.2 channels containing identified mutations. RESULTS: We discovered 2 additional de novo SCN2A mutations. One mutation, SCN2A-E1211K, was identified in a patient with sporadic infantile spasms. SCN2A-E1211K produced channels with altered electrophysiologic properties compatible with both augmented (an approximately 18-mV hyperpolarizing shift in the voltage dependence of activation) and reduced (an approximately 22-mV hyperpolarizing shift in the voltage dependence of steady-state inactivation and a slowed recovery from inactivation) channel activities. The other de novo mutation, SCN2A-I1473M, was identified in a patient with sporadic neonatal epileptic encephalopathy. SCN2A-I1473M caused an approximately 14-mV hyperpolarizing shift in the voltage dependence of activation. CONCLUSIONS: The identified de novo mutations SCN2A-E1211K, -I1473M, and -R102X indicate that SCN2A is an etiologic candidate underlying a variety of intractable childhood epilepsies. The phenotypic variations among patients might be due to the different electrophysiologic properties of mutant channels.

An (CA)n dinucleotide repeat polymorphism of the interleukin-6 (IL-6) gene is associated with metacarpal bone mineral density in hemodialysis patients.

Genetic factors may play an important role in the pathogenesis of reduced bone mineral density (BMD). IL-6 is a multifunctional cytokine and a candidate gene for regulation of bone mineral density (BMD). The relationship between a microsatellite polymorphism of the IL-6 gene and metacarpal BMD in Japanese hemodialysis patients was examined. We selected 165 patients (96 males and 69 females) with a mean age of 62.0 +/- 13.7 years (mean +/- standard deviation (SD) in this study. They were dialyzed for an average of 75.8 +/- 60.8 months (mean +/- SD). The microsatellite polymorphism in the IL-6 gene was examined. According to the number of cytosine-adenine repeats, varying from 13 to 18, 6 alleles could be distinguished. Patients were categorized based on the presence or absence of the allele with 126 bp (i.e. 14 CA repeats) (allele A, all others allele O). The frequencies of IL-6 gene genotypes in hemodialysis patients were 16.4% for OO, 52.1% for AO and 31.5% for AA. The BMD score adjusted for age and body weight (Z score) in the AA genotype group (-0.93 +/- 1.17) was significantly lower than that in the OO (-0.09 +/- 1.42, mean +/- SD, p < 0.005) or AO group (-0.48 +/- 1.15, mean +/- SD, p < 0.01). Serum intact PTH in the OO genotype group (79.3 +/- 84.6) was lower than that in the AA (120.8 +/- 113.6, mean +/- SD, p 0.10) or AO group (132.1 +/- 106.5, mean +/- SD, p < 0.05). These results suggest that polymorphism of the IL-6 gene may be a useful marker for reduced BMD.

Susceptibility and negative epistatic loci contributing to type 2 diabetes and related phenotypes in a KK/Ta mouse model.

The KK/Ta mouse strain serves as a suitable polygenic model for human type 2 diabetes. Using 93 microsatellite markers in 208 KK/Ta x (BALB/c x KK/Ta)F1 male backcross mice, we carried out a genome-wide linkage analysis of KK/Ta alleles contributing to type 2 diabetes and related phenotypes, such as obesity and dyslipidemia. We identified three major chromosomal intervals significantly contributing to impaired glucose metabolism: one quantitative trait locus for impaired glucose tolerance on chromosome 6 and two loci for fasting blood glucose levels on chromosomes 12 and 15. The latter two loci appeared to act in a complementary fashion. Two intervals showed significant linkages for serum triglyceride levels, one on chromosome 4 and the other on chromosome 8. The KK allele on chromosome 8 acts to promote serum triglyceride levels, whereas the KK allele on chromosome 4 acts to suppress this effect in a recessive fashion. In addition, it is suggested that the chromosome 4 locus also acts to downregulate body weight and that the chromosome 8 locus acts to upregulate serum insulin levels. Our data clearly showed that each disease phenotype of type 2 diabetes and related disorders in KK/Ta mice is under the control of separate genetic mechanisms. However, there appear to be common genes contributing to different disease phenotypes. There are potentially important candidate genes that may be relevant to the disease.

Dilazep hydrochloride, an antiplatelet drug, inhibits lipopolysaccharide-induced mouse mesangial cell IL-6 secretion and proliferation.

BACKGROUND: Antiplatelet agents have been widely used to reduce proteinuria and to prevent the progression of chronic glomerulonephritis or diabetic nephropathy to end-stage renal failure. Dipyridamole, one type of antiplatelet drug, inhibits the proliferation of glomerular mesangial cells (MCs). The effect of dilazep hydrochloride (dilazep) on these cells is still obscure. The effects of dilazep on cultured MC IL-6 secretion and proliferation were investigated in the present study. METHODS: IL-6 secretion from MC induced by bacterial lipopolysaccharide (LPS) were assessed using sandwich ELISA. LPS-induced MC proliferation was detected by 3H-thymidine incorporation and WST-1 assay (similar to MTT assay). RESULTS: Incubation of MCs with various dosages of LPS (0, 1, 10, 50 and 100 ng/ml) induced IL-6 secretion in a dose-dependent manner. However, dilazep significantly inhibited this LPS-induced IL-6 secretion from MCs in a dose- and time-dependent manner. Dilazep also significantly inhibited MC proliferation in a dose-dependent manner. CONCLUSION: It appears that these effects of dilazep may prevent progression of mesangial proliferative glomerulonephritis.

Association of the DD genotype and development of Japanese type 2 diabetic nephropathy.

We determined the insertion/deletion (I/D) polymorphism of the angiotensin-coverting enzyme (ACE) gene in a multicenter trial of ethnically homogeneous Japanese type 2 diabetes mellitus (DM) patients. All patients (n = 748) were divided into 5 groups as follows: group I (normoalbuminuric patients), group II (microalbuminuric patients), group III (overt albuminuric patients with serum creatinine (s-Cr) levels of less than 1.2 mg/dl), group IV (overt albuminuric patients with s-Cr levels of more than 1.3 mg/dl but excluding hemodialysis patients), and group V (hemodialysis patients). We selected patients with a diabetic duration of more than 15 years in the mild stage (groups I and II), but placed no limits on those in the advanced and end-stages (groups III, IV and V). The frequency of the DD genotype was slightly higher in the advanced and end stages. The frequency of the DD genotype in the mild stage differed from that in the end stage (II/ID/DD 47.8%/41.0%/11.2% vs. 37.0 %/43.3%/19.7% p = 0.07, II + ID/DD 88.8%/11.2% vs. 80.3%/19.7%, p < 0.05). D allele frequency in the mild stage also differed from that in the end stage (I/D 68.3%/31.7% vs. 58.7%/41.3%, p < 0.02). The presence of the DD genotype increased the risk of end-stage renal disease (ESRD) more than that of the other genotypes (odds ratio ID/II = 1.37, 95% CI 0.82-2.27; DD/II = 2.27, 95% CI 1.12-4.61). It appears that the DD genotype is associated with progression of Japanese type 2 diabetic nephropathy.

Effect of calcium channel blockers, nifedipine and benidipine, on death of cultured mouse mesangi al cells.

We examined the effects of the short-acting calcium channel blocker (CCB) nifedipine and the long-acting CCB benidipine on the death of mouse cultured mesangial cells induced by tumor necrosis factor alpha (TNF-alpha) and/or cycloheximide (CHX). Cell death was evaluated by a morphological study using semithin sections. The dead cells were divided into three types, i.e., apoptotic cells (type 1), necrotic cells (type 3) and other types of dead cells, the so-called 'secondary necrotic cells' or 'postapoptotic necrotic cells' (type 2). In the morphological study with semithin sections, cells in the presence of TNF-alpha or CHX and nifedipine or benidipine showed low percentages of all dead cell types with 24 h incubation. Both nifedipine and benidipine have protective effects against TNF-alpha or CHX. It is postulated that CCB might inhibit the apoptotic or necrotic processes by TNF-alpha or CHX with 24 h incubation. With 36 h incubation, CCB increased the percentages of all types of dead cells except for treatment with 1x10(-5) M benidipine and CHX. It appears that these cell-protective effects might be decreased after treatment with TNF-alpha or CHX and CCB for 36 h. In conclusion, the short-acting CCB nifedipine and the long-acting CCB benidipine have protective effects on mouse cultured mesangial cells against TNF-alpha or CHX. However, nifedipine and benidipine did not inhibit specific types of cell death using semithin sections in this study.

Relationship between polymorphism in the angiotensinogen, angiotensin-converting enzyme or angiotensin II receptor and renal progression in Japanese NIDDM patients.

We determined the relationship between the gene polymorphism of angiotensinogen (AGT), angiotensin-converting enzyme (ACE), or angiotensin II receptor (AT1R) and the progression of diabetic nephropathy in a multicenter trial of ethnically homogeneous Japanese patients with non-insulin-dependent diabetes (NIDDM). Gene polymorphism of ACE I/D, AGT M235T and AT1R A1166C was determined by polymerase chain reaction amplification using allele-specific primers. Japanese NIDDM patients (n = 1,152) were selected from several diabetic clinics. All patients were divided into three groups as follows: (1) group I (n = 407): normoalbuminuric patients; (2) group II (n = 327): microalbuminuric patients, and (3) group III (n = 418): overt albuminuric patients. Clinical factors for investigation in all patients were the date of birth, gender, levels of urinary albumin excretion, findings of the ocular fundus, duration of diabetes, hemoglobin A1c and blood pressure. It appears that genetic polymorphisms in the renin-angiotensin systems, i.e. ACE or AT1R, may affect the progression to renal failure of patients (especially females) with NIDDM.

Detection of cell death of cultured mouse mesangial cells induced by oxidized low-density lipoprotein.

The objectives of the present study using cultured mouse mesangial cells (MMC) were (1) to evaluate the type of cytotoxicity induced by oxidized (ox) LDL, i.e. apoptosis, necrosis and types of other cell death and (2) to investigate the pathway of cell death under incubation with antioxidants or scavenger receptor (SR) antagonists. LDH release and a morphological examination were used in this study. Trypan blue staining of MMC was performed to detect dead cells in culture. Cytotoxicity of ox-LDL in MMC was found to be dose- and time-dependent. In the morphological study of electron microscopy, three different types of cell death in ox-LDL-treated MMC were identified. In the morphological study with semithin sections, these three types of dead cells were identified at different dosages of ox-LDL. Type 1 or type 2 dead cells were observed in low dose ox-LDL or in middle-dose ox-LDL-treated MMC, respectively. Type 3 dead cells were marked in high dose ox-LDL-treated MMC. It appears that the cells were apoptotic (type 1), necrotic (type 3) and other types (type 2). The cytotoxicity of ox-LDL was not mediated by cellular internalization of ox-LDL via SRs. On the other hand, the cytotoxicity of ox-LDL was inhibited by antioxidants such as alpha-tocopherol, probucol, N-acetyl-cysteine or glutathione ethyl ester. It is indicated that the pathways of ox-LDL induced cell death were distinct from the pathway via SRs.

Dissociated expression of collagen type IV subchains in diabetic kidneys of KKAy mice.

Diabetic nephropathy is characterized by thickening of the glomerular basement membrane and expansion of the mesangial matrix. The glomerular basement membrane is assembled from at least five genetically distinct collagen IV chains. In patients with diabetic nephropathy, differential distribution of these components has been demonstrated. In order to clarify the relationship between progression of diabetic nephropathy and altered type IV collagen assembly in the renal cortex, we examined steady state mRNA levels encoding collagen IV subchains in the kidney cortices of spontaneously diabetic KKAy mice and nondiabetic C57black mice as controls. They were sacrificed at 4, 8, 16, and 24 weeks of age. Northern and dot blot analyses were performed using 32P-labeled mouse probes for classical alpha1(IV) and alpha2(IV) and for alpha3(IV), alpha4(IV), and alpha5(IV) minor chains. The mRNA levels for all collagen IV chains peaked at 4 weeks of age and declined rapidly thereafter in the nondiabetic mice. At all times, alpha1(IV) and alpha2(IV) mRNA expressions were abundant and almost unchanged in KKAy mice. In contrast, mRNA levels for alpha3(IV), alpha4(IV), and alpha5(IV) progressively changed with age. It appears that the expression of minor collagen IV chains is dissociated from the alpha1(IV) and alpha2(IV) chains in diabetic nephropathy. Moreover, an unbalanced increase in the production may affect collagen IV assembly and contribute to basement membrane thickening in diabetic nephropathy of KKAy mice.

Inhibition of ileal Na+/bile acid cotransporter by S-8921 reduces serum cholesterol and prevents atherosclerosis in rabbits.

The ileal Na+/bile acid cotransporter (IBAT) plays an important role in the enterohepatic circulation of bile acids. We investigated the effects of IBAT inhibition on the maintenance of serum cholesterol level by using a novel IBAT inhibitor, S-8921, in rabbits. Administration of S-8921 by its incorporation into the diet (0.01% to 0.1%) for 1 to 2 weeks in heterozygous Watanabe heritable hyperlipidemic rabbits decreased serum cholesterol by 29% to 37% and increased fecal excretion of measured bile acids by 60% to 180% compared with control rabbits. Liver microsomal cholesterol 7alpha-hydroxylase and 3-hydroxy-3-methylglutaryl coenzyme A reductase activities were increased by 75% to 84% and 84% to 89%, respectively, with S-8921 treatment. S-8921 administration (0.1% in the diet) to normal New Zealand White rabbits for 2 weeks resulted in increased hepatic low density lipoprotein receptor expression, which was assessed by Northern blot analysis. In cholesterol-fed New Zealand White rabbits, S-8921 treatment (0.003% to 0.1% in the diet) for 10 weeks dose-dependently inhibited the development of hypercholesterolemia. It also inhibited the accumulation of cholesterol in the aortic arch and reduced the severity of coronary atherosclerosis. These results indicate that IBAT inhibition by S-8921 affects serum cholesterol, liver enzymes, low density lipoprotein receptor activity, and atherosclerosis in the same manner as bile acid sequestrants. We suggest that an IBAT inhibitor such as S-8921 could be useful in the treatment of hypercholesterolemia.

Monoclonal antibody P-31 recognizes a novel intermediate filament-associated protein (p250) in rat podocytes.

The visceral glomerular epithelial cells (GECs) or podocytes of the renal glomerulus constitute a highly specialized epithelium. To study the nature of podocytes, we established mouse monoclonal antibodies against GEC. Clone P-31 reacted exclusively with the cytoplasm of GEC by immunofluorescence. Immunoblot analysis with P-31 showed that a single band of 250 kDa was detectable in a glomerular lysate. The 250-kDa polypeptide (p250) was recovered from Triton X-100-insoluble fractions of isolated glomeruli, suggesting that this molecule is associated with the cytoskeleton. Immunogold staining with P-31 demonstrated that the gold particles were located at the intersections of vimentin-type intermediate filaments of podocytes. In developing kidney, this protein first appeared in immature GECs during the S-shaped body stage. In puromycin aminonucleoside nephrosis, p250 was dramatically increased in glomeruli where enhanced desmin expression was observed in GECs. These results indicate that p250 is a novel intermediate filament-associated protein and plays a role in the organization of the intermediate filament network in both normal and diseased conditions.

O/W lipid emulsions for parenteral drug delivery. IV. Changes in the pharmacokinetics and pharmacodynamics of a highly lipophilic drug, menatetrenone.

The pharmacokinetics and pharmacodynamics of antihemorrhagic vitamin, menatetrenone after intravenous injection as the lipid emulsion, were compared to those as the micellar solutions. Menatetrenone was selectively delivered to the liver, lungs and spleen and retained in them. Hepatic and splenetic concentration at 6 h (C6h) increased 21.6- and 27.1-fold, respectively, and the area under the tissue concentration-time curve up to 6 h (AUC(0-6h)) were 2.3- and 11.4-fold, respectively, when compared with its micellar solution. Antihemorrhagic effect of menatetrenone was assessed using warfarin-induced hypoprothrombinemic rats. The lipid emulsion of menatetrenone decreased the prothrombin time at 6h after intravenous injection more effectively than micellar solution. The dose response curves indicated that the efficacy of the lipid emulsion was 2.4-2.9 times that of a micellar solution, and this was correlated with AUC(0-6h) rather than C6h. The plasma level of clotting factor VII and the hepatic level of descarboxyprothrombin were also recovered more effectively, while no significant differences were noted between the two formulations for the plasma level of factor II or descarboxyprothrombin at the dose levels examined. Although selective delivery of menatetrenone in the liver by the lipid emulsion was due to phagocytosis by non-parenchymal cells, menatetrenone in the whole liver appeared to contribute to recovery from hypoprothrombinemia.

Lysophosphatidylcholine promotes cholesterol efflux from mouse macrophage foam cells.

We examined the effects of lysophosphatidylcholine (lyso-PC) on promoting cholesterol efflux from macrophage foam cells. Mouse peritoneal macrophages were converted to foam cells by incubation with [3H]cholesteryl linoleate-labeled or unlabeled acetyl-LDL. When these cells were incubated with lyso-PC, [3H]cholesterol release was promoted in relation to both dose and time, and cellular cholesterol mass was decreased, while medium cholesterol mass was increased. These cholesterol efflux-promotive effects of lyso-PC were confirmed by the fact that the lyso-PC-treated cells showed less oil red O staining than the control cells. ApoE secretion, estimated by Western blotting of the medium, was also augmented by lyso-PC. Both the cholesterol and apoE released by lyso-PC treatment were floated by ultracentrifugation of the medium after its density had been adjusted to 1.210 g/mL. By electron microscopic analysis, vesicular lipoproteins were observed in ultracentrifugally concentrated conditioned medium of lyso-PC. Monensin, a protein secretion inhibitor, effectively inhibited [3H]cholesterol release induced by lyso-PC but not by apoA-I. These results suggest that lyso-PC may inhibit the development of atherosclerosis or enhance its regression by stimulating cholesterol efflux from macrophage foam cells.

[Sarcoidosis representing multiple splenic nodules in a patient with IgA nephropathy].

We have encountered a 49-year-old female with persistent proteinuria and hematuria. Blood pressure, renal function, physical findings and chest X-p showed no abnormality, but blood tests disclosed mild thrombocytopenia, elevated serum ACE activity, serum lysozyme activity and serum IgA concentration. Abdominal echography and CT revealed multiple nodules in her spleen. In order to make a definite diagnosis and exclude the possibilities of malignant lymphoma or metastatic malignant tumor, splenectomy, and open renal biopsy were performed at the same time. On histological examinations, light microscopic appearance of the spleen was characterized by non-caseating granulomas compatible with sarcoidosis. Renal biopsy specimen showed diffuse proliferative glomerulonephritis with positive staining of IgA predominantly located in the mesangial area, compatible with IgA nephropathy. The present case may provide suggestive evidence for a link between sarcoidosis and IgA nephropathy in the pathogenesis. IgA nephropathy complicated by sarcoidosis is rare, and thus is of particular interest because common immunological abnormalities might be considered in the disease process of both diseases. We feel that despite a low index of suspicion, physicians must be alert to the possibility of IgA nephritis associated with sarcoidosis. The literature is reviewed regarding the relationship between IgA nephropathy and sarcoidosis.

Rhabdomyolysis associated with bacteremia due to Streptococcus viridans.

A 25-year-old man was admitted with complaints of fever and macrohematuria. Laboratory tests showed a substantial increase in serum creatine phosphokinase and creatinine in association with myoglobinuria and proteinuria. Blood culture grew Streptococcus salivarius and Streptococcus oralis. Findings of renal biopsy were compatible with IgA nephropathy. The glomeruli had a mild mesangial proliferation without crescentic lesions. Changes of the interstitium and tubules were not evident. The clinical course and laboratory results strongly suggested a possible link between Streptococcus salivarius/oralis infection, and rhabdomyolysis. Rhabdomyolysis is rarely seen as a complication of bacterial infection, and the present case emphasizes the importance of suspecting bacteremia due to Streptococcus salivarius/oralis in the presence of rhabdomyolysis.

[Bacterial intracavernous carotid aneurysm presented as massive epistaxis].

A 55-year-old man was admitted with complaints of headache, diplopia, fever and swelling of the right eyelid. Physical examination revealed low grade fever of 37.6 degrees C, but no evidence of infectious focus was detected. The neurological examination disclosed right abducens nerve palsy. An initial routine blood count showed an increased white blood cell count of 11,800/microliters. The erythrocyte sedimentation rate was 93mm and the C-reactive protein level was 3.6mg/dl. Massive epistaxis and hypovolemic shock developed on the 14th day while the patient was receiving antibiotics (CEZ, CMZ) for a possible intracranial infection. The magnetic resonance angiography of the brain and the cerebral angiography demonstrated an aneurysm within the cavernous sinus, which had not been present on the admission. Since epistaxis was caused by a rupture of the aneurysm, internal carotid artery ligation was done. The signs of inflammation improved as well as patients' symptoms. The improvement while using antibiotics strongly implies that the aneurysm was a result of bacterial infection of the cavernous sinus. There have been no reports of ruptured bacterial intracavernous aneurysms presented with massive epistaxis as this case.

[A 54-year-old man with generalized muscle atrophy and oculomotor paresis].

We report a 54-year-old man with progressive generalized muscle atrophy and ophthalmoparesis in the terminal stage. He was well until 44 years of age (1982) when he noted weakness in his right hand and muscle atrophy; in May of 1985, he noted weakness in his left hand and in both legs. His weakness had become progressively worse, and he became unable to walk in November of 1985. He noted dysarthria one month later, and dysphagia in March of 1986. His difficulty in swallowing had also become worse; he regurgitated foods into the trachea in September of that year, and he developed a low grade fever on the same day. He was admitted to our service on September 24, 1987. On physical examination, general findings were unremarkable, except for low grade fever (37.3 degrees C). On neurologic examination, he was alert and mentally sound. He had normal vision and visual fields; ocular movements were normal. He had moderate weakness in facial muscles, dysarthria, dysphagia, and atrophy in his tongue. He had marked generalized muscle atrophy with fasciculation. He was unable to stand or walk. His muscle strength was not more than 1/6 in any part. The lower extremities were spastic. Deep reflexes were exaggerated in both lower extremities but were normal in upper extremities. Sensation was intact. Laboratory examination was unremarkable, and so was the cranial CT scan. He was treated with nasogastric feeding. He was able to communicate smoothly using his eyes, but a restriction in the vertical gaze was noted in February of 1989. The range of ocular movement was better in the oculocephalic reflex compared with his spontaneous vertical eye movements. In April of 1990, his horizontal gaze also had become slow, and he was complicated by bronchial asthma. He was treated with 20 mg/day of prednisolone; after the institution of prednisolone, his horizontal eye movement showed much improvement. In the terminal stage, he was able to move his eyes only very slowly; vertical gaze was impossible. His subsequent course was complicated by respiratory tract infection and septicemia, and he expired on July 15, 1992. The patient was discussed in a neurological CPC, and the chief discussant arrived at the conclusion that this patient had amyotrophic lateral sclerosis with oculomotor paresis. Post-mortem examination revealed spongy change involving the posterior column and the posterior spinocerebellar tract, in addition to severe degenerative change in the upper and the lower motoneurons, which were consistent with amyotrophic lateral sclerosis.(ABSTRACT TRUNCATED AT 400 WORDS)