Biomedical subjects

H Kato

Publications and source records attributed to H Kato.

At least 487 records · Page 27Linked to original sources

PubMed1999

Identification of a genetic risk factor for systemic juvenile rheumatoid arthritis in the 5'-flanking region of the TNFalpha gene and HLA genes.

OBJECTIVE: To study polymorphisms in the 5'-flanking promoter/enhancer region of the tumor necrosis factor alpha (TNFalpha) gene and in the coding regions of HLA class I and class II genes, in order to better understand the genetic background of juvenile rheumatoid arthritis (JRA). METHODS: One hundred eleven Japanese JRA patients (50 with systemic disease, 29 with pauciarticular disease, and 32 with polyarticular disease) and 575 healthy Japanese subjects were examined for the allele frequencies of the TNFalpha, HLA-A, and HLA class II (DRB1, DRB3, DRB4, DRB5, DQA1, DQB1, DPA1, and DPB1) genes, by DNA typing using the polymerase chain reaction-sequence-specific oligonucleotide probe method. RESULTS: The frequencies of the polymorphic allele at positions -1,031 (T to C substitution, termed -1,031C), -863 (C to A, termed -863A), and -857 (C to T, termed -857T) of the TNFalpha gene in patients with systemic JRA, but not in those with polyarticular or pauciarticular JRA, were significantly higher than in the healthy controls. The allele frequencies of DRB1*0405 and DQB1*0401 in systemic JRA, but not in the other JRA types, were significantly higher than in controls. Linkage analysis showed that the presence of both the TNFalpha -857T allele and DRB1*0405 yielded a significantly increased odds ratio (3.84), while the presence of only 1 of them did not yield a high odds ratio (0.87 and 1.58). CONCLUSION: The -1,031C/-863A allele and the -857T allele of the TNFalpha gene, both of which are related to high production of tumor necrosis factor alpha, are associated with systemic JRA. The -857T allele may enhance the effect of the DRB1*0405/DQB1*0401 haplotype in predisposing to development of systemic JRA.

Arthritis, Juvenile↗

PubMed1999

Multicenter study of paroxysmal dyskinesias in Japan--clinical and pedigree analysis.

To investigate the clinical features of paroxysmal dyskinesias and carry out a pedigree analysis, we conducted a multicenter survey in Japan. A questionnaire was mailed to 229 medical institutions. A total of 150 patients with paroxysmal kinesigenic choreoathetosis (PKC), including 53 sporadic cases and 97 affected individuals from 32 pedigrees, were identified. The mean age of onset of PKC was 8.8 years, and 80% of the cases were men. Of the 32 pedigrees with familial occurrence, 18 (56%) were compatible with an autosomal-dominant inheritance (AD) with complete penetrance, and seven (22%) had AD with incomplete penetrance; the remaining seven were sibling recurrence cases with apparently healthy parents. In six of seven familial cases with incomplete penetrance, the disease gene was thought to be transmitted by clinically unaffected females. Paroxysmal dystonic choreoathetosis (PDC) was found in five cases, including two sporadic cases and three affected individuals from two pedigrees; the mean age of onset was 0.6 years, and a male predominance was noted (male:female = 4:1). There was one case of paroxysmal hypnogenic dyskinesia and one case of paroxysmal exertion-induced dyskinesia. There is an unexplained male predominance for paroxysmal dyskinesias. When the genetic defect of patients with paroxysmal dyskinesias is identified, the pathophysiology of the disease will become more clear.

Adolescent↗

PubMed1999

Deranged blood coagulation equilibrium as a factor of massive liver necrosis following endotoxin administration in partially hepatectomized rats.

Activated Kupffer cells provoke massive liver necrosis after endotoxin stimulation through microcirculatory disturbance caused by sinusoidal fibrin deposition in rats undergoing 70% hepatectomy. In these rats, serum activities of purine nucleoside phosphorylase (PNP) and alanine transaminase (ALT) were increased at 1 and 5 hours, respectively, following endotoxin administration. When 70% resected liver was perfused with Dulbecco's modified Eagle medium (DMEM) containing heat-inactivated fetal calf serum, the increase in both enzyme activities was not affected by addition of endotoxin during perfusion, suggesting that activated Kupffer cells injured neither sinusoidal endothelial cells nor hepatocytes. The activity of tissue factor, an initiator of blood coagulation cascade, was much higher in Kupffer cells isolated from partially hepatectomized rats than in those from normal rats. In contrast, mRNA expressions of tissue factor pathway inhibitor (TFPI) as well as thrombomodulin were almost undetectable in normal and partially resected livers. When recombinant human TFPI was injected intravenously in 70% hepatectomized rats, TFPI was markedly stained on the surfaces of sinusoidal endothelial cells and microvilli of hepatocytes on immunohistochemistry. In these rats, endotoxin-induced liver injury was significantly attenuated compared with rats given no TFPI. Similar attenuation was also found in rats receiving recombinant human thrombomodulin. These results suggest that fibrin deposition developing in 70% hepatectomized rats after endotoxin administration may be caused by deranged blood coagulation in the hepatic sinusoids through increasing tissue factor activity in Kupffer cells and minimal TFPI and thrombomodulin in endothelial cells. The destruction of sinusoidal endothelial cells as well as hepatocytes may occur as a result of microcirculatory disturbance caused by such sinusoidal fibrin deposition.

Alanine Transaminase↗

PubMed1999

Cytokine regulation of env gene expression of human endogenous retrovirus-R in human vascular endothelial cells.

To determine whether human endogenous retroviruses are implicated in the pathogenesis of inflammatory vascular diseases of unknown etiology, we examined mRNA expression of a human endogenous retrovirus, HERV-R, which has a long open reading frame in the env region, in cultured human vascular endothelial and smooth muscle cells stimulated in the presence of various cytokines. mRNA of HERV-R was always evident in these cells but not in fibroblastic cells. Levels of expression in vascular endothelial cells were significantly regulated by treatment with tumor necrosis factor-alpha, interleukin (IL)-1alpha, and IL-1beta as up-regulators and interferon-gamma as a down-regulator. These observations are interpreted to mean that HERV-R expression may be up- or down-regulated at sites of inflammation in vessels in vivo and hence may play a pathogenetic role in inflammatory vascular diseases in humans, perhaps similar to endogenous retroviruses in mouse models of polyarteritis nodosa in humans.

Cells, Cultured↗

PubMed1999

Comparison of pathogenic factors expressed by group A Streptococci isolated from patients with streptococcal toxic shock syndrome and scarlet fever.

Streptococcal toxic shock syndrome (STSS) is an illness with high mortality. To obtain clues to understanding the pathogenesis of STSS, we investigated the expression of several pathogenic factors in ten group A streptococcus (GAS) isolates from ten patients with STSS in Japan, in comparison with ten GAS isolates from children with scarlet fever. The ten scarlet fever-derived GAS isolates were equally low in lethality and anti-phagocytic activity in mice and in the production of streptolysin O (SLO), and equally high in production of superantigenic exotoxins (SAGTs) and cysteine proteinase. By comparison, the ten STSS-derived GAS isolates were heterogeneous in the expression of the above pathogenic factors, which ranged from low to high values. Most of the ten STSS-derived isolates were higher in lethality and anti-phagocytic activity and production of SLO, and lower in the production of SAGTs and cysteine proteinase than the ten scarlet fever-derived isolates. The results suggest that the lethality and anti-phagocytic activity examined in mice and SLO may be involved mainly in the development of most of the ten STSS cases.

Animals↗

PubMed1999

A case of pseudosarcoma associated with type 3 squamous cell carcinoma of the esophagus: report of a case.

A case of a primary esophageal pseudosarcoma associated with an independent type 3 tumor is described herein. A 60-year-old male presented with dysphagia and chest discomfort. A clinical evaluation revealed a type 3 tumor in the middle of the esophagus, which was diagnosed after a biopsy to be squamous cell carcinoma (SCC). A subsequent gross examination of the subtotally removed esophagus revealed a polypoid tumor adjacent to the type 3 tumor. Histologically, the polypoid mass was composed of SCC and mesenchymal components without a transitional zone. The tumor was thus classified as a pseudosarcoma of the esophagus, and was unique in that this appeared to have developed independently from the SCC.

Carcinoma, Squamous Cell↗

PubMed1999

Thermal distribution of radio-frequency inductive hyperthermia using an inductive aperture-type applicator: evaluation of the effect of tumour size and depth.

A new radio-frequency (RF) inductive hyperthermia device using an inductive aperture-type applicator (IATA) is proposed. This paper reports the evaluation of the heating characteristics of the IATA using a computer simulation and clinical thermal parameters obtained during treatment of superficial and subsurface-seated tumours. The configuration of the IATA is a one-turn square column-like coil whose bottom plate is set to face the heating target. The IATA has advantages over RF capacitive-type heating, such as: generating less heat in the subcutaneous fat layer; less convergency of electric line of force at the edge of the applicator; and no physical contact with the target lesion. The induced magnetic fields and electrical currents within the heating substance are simulated using computer-assisted design software for electro-magnetic analysis. A total of 40 superficial and subsurface tumours are treated with the IATA. Invasive thermometry is performed continuously for 110 sessions using multi-sensor probes of an optical thermometer. Thermal parameters (Tmax, Tmin, Tave) are assessed based on the tumour size and depth. The treated tumours are categorised into three groups according to tumour depth: group 1 (< 3 cm, n = 28), group 2 (3-5 cm, n = 35) and group 3 (> 5 cm, n = 47). The computer simulation shows that induced electrical currents run without convergency, parallel to the surface of the heating material. All thermal parameters of group 3 are significantly higher than those of group 1 and 2 (p < 0.05), indicating that the larger lesions tend to abtain a higher temperature distribution. In conclusion, RF inductive hyperthermia using the IATA results in effective temperature distributions in superficial and subsurface tumours, with large tumours being most effectively heated.

Aged↗

PubMed1999

Functional Analysis of Promoter Region from Eel Cytochrome P450 1A1 Gene in Transgenic Medaka.

: Transcription of the CYP1A1 genes in mammals and fish is stimulated by polyaromatic hydrocarbons. DNA sequencing analysis revealed that CYP1A1 gene in eel (Anguilla japonica) contains two kinds of putative cis-acting regulatory elements, XRE (xenobiotic-responsive element) and ERE (estrogen-responsive element). XRE is known as the enhancer that is responsible for the inducibility of the genes of CYP1A1 and some other drug-metabolizing enzymes. In the eel CYP1A1 gene, XRE motifs are distributed as follows: five times in the region from -2136 to -1125 bp, XRE(-6) to (-2); once in the proximal basal promoter region, XRE(-1); and once in the first intron, XRE(+1). The region between XRE(-2) and XRE(-1) contains three ERE motifs. To investigate the function of the cis-acting regulatory elements in the eel CYP1A1 gene, recombinant plasmids prepared with its 5' upstream sequence and the structural gene for luciferase were microinjected into fertilized eggs of medaka at the one-cell stage. Hatched fry were treated with 3-methylcholanthrene, and the transcription efficiency was assayed using competitive polymerase chain reaction analysis. Deletion of the region containing the five XREs, XRE(-6) to XRE(-2), and the point mutation of XRE(-1) reduced the inducible expressions by 75% and 56%, respectively, showing apparent dependency of the drug induction on the XREs. Constitutive expression, however, was not significantly affected by deletion or disruption of the XREs. When the region between XRE(-2) and XRE(-1) containing no XREs but three ERE motifs was internally deleted, the inducible expression and the constitutive expression were reduced by 88% and 75%, respectively. Replacement of this region with a partial fragment of eel CYP1A1 complementary DNA, with slight alteration of the distance between the five XREs and XRE(-1), reduced the inducible expression and the constitutive expression by 91% and 60%, respectively. These results strongly suggest that not only XRE but also other regulatory elements, possibly ERE, play an important role in induced and constitutive expressions of the eel CYP1A1 gene.

Journal Article↗

PubMed1999

Isolation and Sequence Analysis of the Eel Cytochrome P450 1A1 Gene.

: The putative CYP1A1 gene was isolated from a genomic library of eel (Anguilla japonica) chromosomal DNA. Sequence analysis of 8184 bp showed that the clone obtained was the structural gene of CYP1A1, which consisted of seven exons and six introns in a region approximately 5800 bp in length, as well as a 5' upstream region of about 2300 bp. The initiation codon was found not in the first exon, but in the second exon, as was reported for the CYP1A genes of mammals and fish. The GC box, CAAT box, and TATA box were located proximately to the first exon, at 110, 62, and 38 bp upstream of the transcriptional start site, respectively. We found six core sequences of xenobiotic-responsive elements (XREs) in the 5' upstream region, and also one in the first intron. All the XRE core sequences in the 5' upstream region were unique in their localization in the sense strand. The XRE core sequence in the first intron was in the antisense strand.

Journal Article↗

PubMed1999

Hyperinsulinaemic hypoglycaemia associated with persistent hyperammonaemia.

UNLABELLED: Two cases of hyperinsulinaemic hypoglycaemia associated with persistent hyperammonaemia in unrelated infants of 7 days and 4 months of age are reported. Blood ammonia levels were 100-300 micromol/l (normal values <40 micromol/l). The hyperammonaemia was asymptomatic and not associated with any of the abnormalities of amino acids or organic acids observed in urea cycle enzyme defects. Orotic aciduria was normal. The hyperammonaemia was not influenced by the levels of blood glucose nor by subtotal pancreatectomy. On admission blood glucose was ca. 1.2 mmol/l (21.6 mg/dl) corresponding to blood insulin levels of 35 and 22 mU/l respectively in both infants. Continuous intravenous glucose perfusion was necessary to prevent hypoglycaemia. Furthermore 2-oxoglutaric acid in urine was increased in the second infant to 3.15 mg/mg creatinine (normal 0.41+/-0.12). This may point to mutations in the glutamate dehydrogenase gene. CONCLUSION: 2-Oxoglutaric aciduria may be an important clue to the diagnose in this syndrome.

Ammonia↗

PubMed1999

Laparoscopic repair of intestinal malrotation complicated by midgut volvulus.

Intestinal malrotation is rare in older children and adults. We performed laparoscopic repair and treatment for a 13-year-old girl diagnosed as having intestinal malrotation complicated by midgut volvulus. Under laparoscopic vision, the midgut volvulus was untwisted by grasping and pulling the intestine; Ladd's band was divided and broadened; hepatic and splenic flexure of the colon was fixed; and finally an appendectomy was performed. The patient was walking and able to resume oral intake on the first postoperative day. There was no complaint in 6 months of follow-up, and the small incisional scar satisfied the patient and her parents.

Adolescent↗

PubMed1999

Increased cerebrospinal fluid levels of substance P in patients with amyotrophic lateral sclerosis. Short communication.

To clarify the mechanism of brain and spinal cord impairment in amyotrophic lateral sclerosis (ALS), we measured the cerebrospinal fluid (CSF) levels of substance P (SP) in 11 patients with sporadic ALS. Findings were compared with those obtained in controls and diseased controls. The CSF SP levels of patients with ALS, and particularly in patients with a disease duration of less than 2.5 years, were significantly higher than those in controls. These findings strongly suggested that SP may play an important role in the pathophysiology of ALS.

Adult↗

PubMed1999

Extrapontine myelinolysis with parkinsonism after rapid correction of hyponatremia: high cerebrospinal fluid level of homovanillic acid and successful dopaminergic treatment.

Extrapontine myelinolysis (EPM) is a demyelinating process of the brain. We report the case of an 11-year-old girl who developed EPM with parkinsonism. Magnetic resonance imaging revealed demyelinating patterns in the basal ganglia without central pontine lesions. The cerebrospinal fluid levels of homovanillic acid and 5-hydroxyindoleacetic acid were high at the time of onset and normalized upon complete recovery from extrapyramidal symptoms after a dopaminergic treatment. We speculated that demyelination of nerve fibers containing dopamine receptors in the striatum might be a main cause of these symptoms.

Antiparkinson Agents↗

PubMed1999

Effects of the non-competitive NMDA receptor antagonist ifenprodil on the morphine-induced place preference in mice.

The effects of ifenprodil, a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist, on the morphine-induced place preference were examined in mice. Morphine (1-5 mg/kg, s.c.) produced a dose-related place preference in mice. In contrast, ifenprodil alone (5-20 mg/kg, i.p.) did not produce either preference or aversion for the drug-associated place. Pretreatment with ifenprodil (5-20 mg/kg, i.p.) suppressed the place preference produced by morphine in a dose-dependent manner. These results indicate that ifenprodil suppresses the rewarding effect produced by morphine.

Animals↗

PubMed1999

Role of transforming growth factor-beta1 and decorin in development of central fibrosis in pulmonary adenocarcinoma.

Transforming growth factor-beta1 (TGF-beta1) is known as the growth factor that stimulates the synthesis of extracellular matrix. Recently, TGF-beta has been found to control the growth of cancer cells. Small chondroitin-dermatan sulfate (decorin) is an abundant extracellular matrix component. TGF-beta1 stimulates the synthesis of decorin, and decorin is considered to bind TGF-beta1. The activity of decorin in neutralizing TGF-beta1 activity suggests that decorin serves as a negative-feedback regulator of TGF-beta1 activity. To investigate the role and relationship of TGF-beta1 and decorin in the formation of central fibrosis in pulmonary adenocarcinoma, we performed an immunohistochemical study of TGF-beta1 and decorin in 61 cases of T1 pulmonary adenocarcinoma. Positive stainings for TGF-beta1 were shown in 40 cases and negative in 21 cases. Twenty-seven of 32 cases with central fibrosis were positive for TGF-beta1. Positive staining for TGF-beta1 was significantly related to the appearance of central fibrosis in pulmonary adenocarcinoma. When central fibrosis was composed of proliferative connective tissue with loose staining for decorin, cancer cells showed intense staining for TGF-beta1. When central fibrosis was composed of old fibrotic tissue with dense staining for decorin, cancer cells showed weak staining for TGF-beta1. Our results suggest that TGF-beta1 has an important role in the formation of central fibrosis in pulmonary adenocarcinoma, and decorin may play a role as a negative feedback regulator in the production of TGF-beta1 in pulmonary adenocarcinoma.

Adenocarcinoma↗

PubMed1999

In vivo imaging of spontaneous ultraweak photon emission from a rat's brain correlated with cerebral energy metabolism and oxidative stress.

Living cells spontaneously emit ultraweak light during the process of metabolic reactions associated with the physiological state. The first demonstration of two-dimensional in vivo imaging of ultraweak photon emission from a rat's brain, using a highly sensitive photon counting apparatus, is reported in this paper. It was found that the emission intensity correlates with the electroencephalographic activity that was measured on the cortical surface and this intensity is associated with the cerebral blood flow and hyperoxia. To clarify the mechanism of photon emission, intensity changes from whole brain slices were examined under various conditions. The removal of glucose from the incubation medium suppressed the photon emission, and adding 50 mM potassium ions led to temporal enhancement of emission and subsequent depression. Rotenone (20 microM), an inhibitor of the mitochondrial electron transport chain, increased photon emission, indicating electron leakage from the respiratory chain. These results suggest that the photon emission from the brain slices originates from the energy metabolism of the inner mitochondrial respiratory chain through the production of reactive oxygen. Imaging of ultraweak photon emission from a brain constitutes a novel method, with the potential to extract pathophysiological information associated with neural metabolism and oxidative dysfunction of the neural cells.

Animals↗

PubMed1999

High prevalence and phylogenetic analysis of TT-virus infection in Mongolia.

A novel DNA virus, TT-virus (TTV), was isolated from a post-transfusion hepatitis patient in Japan. The prevalence of TTV infection was investigated among patients with chronic liver disease and normal alanine aminotransferase (ALT) volunteers as controls in Mongolia. Polymerase chain reaction (PCR) was employed to detect TTV DNA using specific primers derived from open reading frame 1 (ORF1) of the TTV genome. Nucleotide sequences of samples positive for TTV DNA were determined. The sequences were analyzed by a molecular evolutionary method. Fifty (60.2%) hepatitis patients and 12 (42.9%) volunteers were positive for TTV DNA. The serum ALT levels did not differ significantly between patients with single TTV infection and without TTV, HBV and HCV infection. Similarly, the serum ALT levels did not differ significantly between controls with and without TTV infection. Dual infection of TTV with either HBV or HCV did not affect the ALT levels of hepatitis patients. The molecular evolutionary tree showed that TTV was a heterogeneous virus and all strains could be divided into three genotypes in Mongolia. A new genotype was identified that was distinct from those previously reported.

Adult↗

PubMed1999

TT virus infection among blood donors and patients with non-B, non-C liver diseases in Korea.

BACKGROUND/AIMS: A novel virus, designated the TT virus (TTV), was isolated from the serum of a patient with posttransfusion hepatitis of unknown etiology, in Japan. Subsequently, TTV was suggested to be a causative agent in a proportion of cases with cryptogenic hepatitis in Japan. This study aimed to elucidate the significance of TTV infection in cases with cryptogenic liver disease in Korea, a neighbor of Japan. METHODS: The prevalence of TTV infection was studied in 120 patients with liver diseases, including 85 patients diagnosed as having non-B, non-C liver diseases. As controls, 220 blood donors were also examined. TTV DNA was detected by polymerase chain reaction, and the sequence was analyzed by phylogenetic analysis. RESULTS: Fourteen (14.0%) of 100 accepted blood donors, 23 (19.2%) of 120 rejected blood donors, and 15 (17.6%) of 85 patients with non-B, non-C liver diseases were positive for TTV DNA. The prevalences of TTV infection among these groups were not significantly different. Phylogenetic analysis suggested the existence of four major genotypes of TTV The proportions of each genotype among patients with non-B, non-C liver diseases were not different from those among accepted blood donors. CONCLUSIONS: TTV exists in Korea, but the prevalence among patients with non-B, non-C liver diseases was almost the same as that among blood donors. TTV may not be the main causative agent of cryptogenic liver disease in Korea. The relationship between non-B, non-C liver diseases and TTV genotype remains unclear, although TTV can be classified into four genotypes.

Adolescent↗