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N Kato

Publications and source records attributed to N Kato.

At least 343 records · Page 19Linked to original sources
PubMed1998

Major virulence factors, VacA and CagA, are commonly positive in Helicobacter pylori isolates in Japan.

BACKGROUND: VacA and CagA proteins have been reported to be major virulence factors of Helicobacter pylori. However, antibodies against these proteins are frequently found in the sera of Japanese patients regardless of their gastroduodenal status. AIM: To evaluate the expression of VacA and CagA proteins by H pylori strains isolated in Japan. METHODS: By using specific antibodies raised against recombinant VacA and CagA proteins, the expression of VacA and CagA was evaluated in 68 H pylori strains isolated from Japanese patients; a vacuolating assay and genotyping of the vacA gene were also used in the evaluation. The results in analysed in relation to the gastroduodenal diseases of the hosts. RESULTS: VacA and CagA proteins were expressed in 59/68 (87%) and in 61/68 (90%) isolates respectively. The vacuolating assay was positive in 57/68 (84%) isolates, indicating that most immunologically VacA positive strains produced active cytotoxin. The prevalence of infection with strains expressing CagA and positive for vacuolating activity (Type I) was very high, 54/68 (79%), irrespective of the gastroduodenal status of the host. CONCLUSION: Most H pylori isolates in Japan are positive for vacuolating cytotoxin and CagA, and thus these virulence factors cannot be used as markers to discern the risk of developing serious gastroduodenal pathologies in the hosts. However, the high prevalence of infection with strains positive for vacuolating cytotoxin and CagA may contribute to the characteristics of H pylori infection in Japan.

Adult↗
PubMed1998

Practicable approaches to targeted comparative mapping of rat chromosome regions: linkage mapping of five genes on rat chromosome 13.

We demonstrate feasible approaches to comparative mapping between the region near the renin locus on rat chromosome 13 and human chromosome 1q by assigning five additional genes as anchor loci. Base-substitution polymorphisms were sought in the 3'- and/or 5'-untranslated regions for subsequent development of PCR-amplified markers, which, in turn, could be used for either restriction fragment analysis or allele-specific PCR.

Animals↗
PubMed1998

Lack of association between the alpha-adducin locus and essential hypertension in the Japanese population.

Significant linkage and association of alpha-adducin, a cytoskeleton protein involved in transmembrane ion transport, with essential hypertension were recently shown in Caucasian populations, especially in relation to salt sensitivity. The present study investigated the relevance of this candidate gene to hypertension in a well-characterized Japanese population. A total number of 507 individuals were selected from clinic outpatients. Hypertensive subjects were defined on the basis of the individual's blood pressure readings before starting medications; the criteria included systolic blood pressure > or = 160 mm Hg and/or diastolic blood pressure > or = 95 mm Hg. Patients with diabetes mellitus, renal failure, and secondary forms of hypertension had been excluded. Control subjects had blood pressure values < 130/85 mm Hg. The allele frequency of a genetic variant at amino acid residue 460 of alpha-adducin (460Trp) was compared between cases and control subjects with chi(2) statistics; in addition, the association was tested with blood pressure as a continuous variable. No significant association was found in either of the statistics tested. The 460Trp variant appeared to be relatively common in the Japanese (54% to 60%) compared with a reported prevalence of 13% to 23% in Caucasians. The present study brought up an important issue concerning the pathophysiological role of alpha-adducin in non-Caucasian populations, given the likely ethnic variation in the nature of genetic susceptibility loci. The 460Trp variant of the alpha-adducin gene is unlikely to have a major effect on susceptibility to hypertension in the Japanese population studied, although the present study does not exclude the involvement of alpha-adducin in the pathogenesis of hypertension.

Analysis of Variance↗
PubMed1998

G protein beta3 subunit variant and essential hypertension in Japanese.

Enhanced G protein activation has been implicated to underlie the increased sodium-proton transport in blood cells, an impaired characteristic observed in 30% to 50% of patients with essential hypertension. Recently, significant association between a C825T polymorphism of the gene encoding the G protein beta3 subunit and hypertension was demonstrated in a white population, together with the finding that the T825 variant might be related to alternative splicing through unidentified mechanisms. We therefore investigated the disease relevance of this candidate gene by conducting an association study in a relatively large Japanese population. Participants comprised 718 hypertensive case subjects (without diabetes mellitus), 515 normotensive control subjects, and 191 hypertensive subjects with borderline or established diabetes mellitus; all individuals were recruited at a single institution. Genotype distribution of the C825T polymorphism was compared between hypertensive subjects, with or without diabetes, and the control group with chi2 statistics. No significant association was observed in the present study. Results were still not significant when the case group was subdivided according to more stringent classification criteria. Allele frequencies of T825 proved to be almost concordant among the 3 study groups and higher in Japanese (49.0% to 49.6%) compared with a reported prevalence of 25% to 31% in whites. Our data suggest that the T825 variant of the G protein beta3 subunit gene is unlikely to constitute major susceptibility for essential hypertension in the Japanese population studied. However, further investigation is required to answer the question of whether the lack of association reflects ethnic differences in the nature of genetic susceptibility loci.

Aged↗
PubMed1998

Magnetic resonance spectroscopy in affective disorders.

Magnetic resonance spectroscopy (MRS) is a non-invasive tool for in vivo chemical analysis that has been applied to neurobiological or psychopharmacological studies of affective disorders. Studies employing 31P-MRS and 1H-MRS have indicated possible abnormalities in membrane phospholipid metabolism, high-energy phosphate metabolism, and intracellular pH in affective disorders. They have also suggested that lithium increases the phosphomonoester (possibly inositol-1-phosphate) peak in the brain but does not increase that of choline-containing compounds in the brain. Studies employing 7Li-MRS and 19F-MRS have elucidated the pharmacokinetic properties of lithium, fluoxetine, and fluvoxamine in the brain in patients treated with these drugs.

Affect↗
PubMed1998

Dermomyotomal origin of the ribs as revealed by extirpation and transplantation experiments in chick and quail embryos.

To elucidate role of the dermomyotome in the formation of the axial skeleton, we performed extirpation and transplantation experiments on the dermomyotomes in chick and quail embryos. When the thoracic dermomyotomes of chick embryos were removed, the intercostal muscles and the distal ribs were deficient, while the proximal ribs were more or less normal. Quail tissues including the dermomyotome, the ectoderm and the medial edge of lateral plate, were transplanted to replace chick dermomyotomes. In these chimeras, the ribs, which would be deficient without the back-transplantation, were recovered. The cells of the recovered part of the ribs as well as the intercostal muscles were derived from the quail transplants. These findings suggest that the distal rib originated from the dermomyotomes and not the sclerotome as previously believed. To localize the origin of the distal rib further, we removed restricted regions of the dermomyotomes along the mediolateral and the rostrocaudal axis. The more lateral the part of the dermomyotomes that we removed, the more distal the part of the ribs affected. On the contrary, when the rostral and caudal edges of the dermomyotomes were removed, only the vertebral ribs showed extensive deficiencies while removal of the middle part between the edges caused less deficiency. The sternal ribs were not deficient in either case, but were extensively affected when the entire lateral edge of dermomyotomes was included in the region removed. We conclude that the lateral edges of the dermomyotomes are the primordia of the sternal ribs, and the rostral and/or caudal edges of the medial part of dermomyotomes are the primordia of the distal part and not of the proximal part of the vertebral ribs.

Animals↗
PubMed1998

Silk protein, sericin, inhibits lipid peroxidation and tyrosinase activity.

This study provided the first evidence for an antioxidant action of the silk protein sericin by showing that sericin suppressed in vitro lipid peroxidation. Furthermore, sericin was found to inhibit tyrosinase activity. These results suggest that sericin may be a valuable natural ingredient for food and cosmetic industries.

Animals↗
PubMed1998

Hemiacetal dehydrogenation activity of alcohol dehydrogenases in Saccharomyces cerevisiae.

Some methylotrophic yeasts produce methyl formate from methanol and formaldehyde via hemiacetal formation. We investigated Saccharomyces cerevisiae to find whether this yeast has a carboxylate ester producing pathway that proceeds via hemiacetal dehydrogenation. We confirmed that the purified alcohol dehydrogenase (Adh) protein from S. cerevisiae can catalyze the production of esters. High specific activities were observed toward the hemiacetals corresponding to the primary alcohols when ether groups were substituted for methylene groups, resulting in the formation of formate esters. Both ADH and methyl formate synthesizing activities were sharply reduced in the delta adh1 delta adh2 mutant. The ADH1 and ADH2 genes encode the major Adh proteins in S. cerevisiae. Thus, it was concluded that the S. cerevisiae Adh protein catalyzes activities for the production of certain carboxylate esters.

Acetals↗
PubMed1998

Hypercholesterolemic effect in rats of a dietary addition of the nitric oxide synthase inhibitor, L-N omega nitroarginine, by less synthesis of bile acids.

We have previously reported that feeding rats with a diet containing 0.02% L-N omega nitroarginine (L-NNA), a specific inhibitor of nitric oxide synthase, induced hypercholesterolemia. This present study was conducted to examine the underlying mechanism for hypercholesterolemia in rats. In experiment 1, feeding a diet containing 0.02% L-NNA for 5 wk elevated the concentration of serum cholesterol and reduced the excretion of fecal bile acids, but did not affect the excretion of fecal neutral sterols. Reduced activity of hepatic cholesterol 7 alpha-hydroxylase, the rate-limiting enzyme for the biosynthesis of bile acids from cholesterol, was observed in the rats receiving L-NNA. In experiment 2, rats were fed for 5 wk on a diet with or without 0.02% L-NNA that was or was not supplemented with 4% L-arginine. The L-NNA treatment elevated the serum concentrations of total cholesterol, free cholesterol and esterified cholesterol, and reduced the activity of hepatic cholesterol 7 alpha-hydroxylase, serum nitrate (a metabolite of NO) and the ratio of HDL-cholesterol versus serum total cholesterol. These alterations were suppressed by supplementing the L-NNA-containing diet with L-arginine. The results suggest that lower NO production by L-NNA caused hypercholesterolemia by a mechanism involving impaired bile acid synthesis.

Animals↗
PubMed1998

Isolation, characterization, and sugar chain structure of endoPG Ia, Ib and Ic from Stereum purpureum.

Three endopolygalacturonases (endoPG Ia, Ib, and Ic) were isolated from the culture filtrate of Stereum purpureum, the causative fungus of apple silver-leaf disease. Their properties, including specific activities, optimum pHs, thermal stabilities, and kinetic parameters (K(m) and Vmax) were compared. Their properties were very similar to one another except for the substrate specificity and relative molecular mass. The sugar chains of endoPG Is were released by hydrazinolysis, and one major sugar chain common to endoPG Is was isolated. The pyridylamino sugar was characterized by a two-dimensional mapping method using HPLC, and identified as a high mannose type N-linked sugar chain, Man alpha 1-6(Man alpha 1-3)Man alpha 1-6(Man alpha 1-3) Man beta 1-4 GlcNAc beta 1-4 GlcNAc (designated as M5.1). Observation of the course of Western blot analysis for the proteins from the culture filtrate with endoPG I antibodies showed that the fungus secreted three endoPG Is into the culture broth during the growing period.

Amino Sugars↗
PubMed1998

Percutaneous hepatic infarction therapy for hepatocellular carcinoma.

OBJECTIVE: We percutaneously injected ethanol into small vessels afferent to tumor nodules to induce hepatic infarction in areas of tumor caused by hepatocellular carcinoma. CONCLUSION: Percutaneous hepatic infarction therapy holds promise as a new method of treating large hepatocellular carcinoma.

Carcinoma, Hepatocellular↗
PubMed1998

[Magnetic resonance images of hematospermia].

BACKGROUND: We performed MRI (magnetic resonance imaging) in the pelvic region of 70 cases with hematospermia and conducted a study on the abnormal MRI findings to which hematospermia could be attributed. METHODS: We conducted a study on the morphological anomaly and change in the signal intensity in the prostate gland and of the seminal vesicle as well as on the presence or absence of dilation in the plexus venous surrounding the deferent duct or the prostate gland out of the abnormal MRI findings. As for the seminal vesicle, the patients whose seminal vesicle was seen in higher intensity than the prostate gland in T1 weighted images were diagnosed as having hemorrhagic focus and the patients whose seminal vesicle was seen in low intensity both in T1 and T2 weighted images were diagnosed as having fibrosis caused by chronic inflammation. RESULTS: Abnormal MRI findings were seen in 40 out of the 70 cases (57%). Anomaly in the prostate gland was indicated in 6 (9%) cases. Abnormality in the seminal vesicle was indicated in 30 cases (43%) including hemorrhage of seminal vesicle in 25 cases, chronic inflammation in five cases and cyst of seminal vesicle in one case. CONCLUSION: In conducting an examination of the patients with hematospermia, MRI is the noninvasive and reproducible method and it is possible to identify the hemorrhagic region. Therefore, MRI is thought to be useful to identify the causal organs of hematospermia.

Adult↗
PubMed1998

[A clinical study of decreased bone density in the patients treated with long-term luteinizing hormone releasing hormone analogue (LHRH-a)--the risk of iatrogenic osteoporosis due to treatment of carcinoma of prostate].

BACKGROUND: It is well known that androgens play an important role in bone metabolism and male hypogonadism induce osteoporosis. Luteinizing hormone-releasing hormone analogue (LHRH-a) which is essential for conservative therapy of prostatic carcinoma (CaP) ultimately reduces circulating testosterone to castration levels. The purpose of this study was to determine the risk of decrease of bone mineral density in men receiving LHRH-a for CaP. PATIENTS AND METHODS: Fifty-three man with CaP aged 63 to 95 years (mean 75.5 years) were included in this study. Seven patients received LHRH-a with estrogen drug, forty-six patients received LHRH-a with or without anti androgen drug. To estimate patient's bone density we use the second metacarpal bone density using a microdensitometry method. RESULTS: Blood level of sex hormone of the forty-six patients who were received LHRH-a without estrogen, was the same as that of castration. Patients who were treated more than twelve months had less bone density than patients who were treated less than eleven months. As the duration of medical castration period was prolonged, patients bone density were reduced. Whereas seven patients who received estrogen drug did not find a decrease of bone density regardless of duration of treatment period. CONCLUSIONS: Hypogonadism induced LHRH-a also reduce bone density, so there is a risk of iatrogenic osteoporosis caused by therapy for CaP with LHRH-a. Patients with osteoporosis easily suffer from a much complicated and pernicious bone fracture, so we should measure bone density of male patients same as female treated with LHRH-a for a long-term.

Aged↗
PubMed1998

Trend of adenovirus type 7 infection, an emerging disease in Japan. A report of the National Epidemiological Surveillance of Infectious Agents in Japan.

The program of the National Epidemiological Surveillance of Infectious Diseases under the auspices of the Ministry of Health and Welfare started in 1981 apprehended in 1995 emergence of adenovirus type 7 in Japan. We analyzed the reported data of type 7 comparing with those of type 3, both belonging to the same subgenus B, and the following results were obtained: After 1981, the main serotypes in the reports of adenovirus isolation/detection were types 3, 2, and 1 in this order. The reports of isolation of adenovirus type 7 used to be extremely few, however, suddenly increased in 1995. In 1997, reports of isolation of adenovirus type 3 decreased and those of type 7 acquired the third place after those of types 2 and 3. Type 7 infection occur almost every month, but most frequently during May-September. The ages of cases from which type 7 was isolated were 0-4 years accounting for 55%, 5-9 years 35%, teens 6.3% and adults 4.0%, being similar proportions to those yielding type 3. Clinical diagnoses of cases yielding adenovirus type 7 were pharyngo-conjunctival fever (PCF) and influenza-like illness, these two accounting for half. The symptoms were severe, being characterized by higher maximum body temperature during the feverish period and severe pneumonia. Encephalitis and arthro-muscular pain were seen in only type 7-infected cases, although such cases were few.

Adenoviridae Infections↗
PubMed1998

[Bilateral simultaneous epididymal leiomyoma: a case report].

Primary epididymal leiomyoma is relatively rare. We experienced a case of bilateral simultaneous primary epididymal leiomyoma. A 61-year-old man visited our clinic, with the chief complaint of bilateral painless nodules in the scrotum. Each nodule was palpated at the tail of each epididymis (the diameters of these nodules were 12 mm on left and 5 mm on right). We followed the patient for 18 months. Since the nodules were increasing in size, the nodules were surgically removed. Histological examination revealed primary leiomyomas of the epididymis.

Epididymis↗
PubMed1998

Human diseases caused by exotoxins produced by anaerobes and their rapid detection.

Major human diseases caused by exotoxins produced by anaerobes include botulisms, tetanus, foodborne illness caused by enterotoxin-producing Clostridium perfringens, and diarrhea/colitis caused by toxigenic Clostridium difficile. Recently, enterotoxigenic Bacteroides fragilis (ETBF) has been recognized, that may be related to childhood diarrheal disease. Detection test of botulinal neurotoxin is hardly performed at clinical laboratories since the most reliable means of detection and identification of botulinal toxin is by using mouse toxicity and neutralization tests. Clinical laboratories should request the tests to a reference laboratory. Since tetanus is easily diagnosed clinically on the basis of its unique, recognizable sings, the bacteriological tests is not usually requested. C. perfringens foodborne illness can be confirmed by testing stool specimens or the suspect food(s) for enterotoxin by the reversed passive latex agglutination test or counting > 10 5 C. perfringens per g of suspected food or > 10 6 C. perfringens spores per g of stool. Diagnosis of C. difficile-associated diarrhea/colitis is confirmed by detection of toxins A or B of C. difficile and/or recovery of toxigenic C. difficile. Isolation of C. difficile strains or detection C. difficile-speciffic antigen from stool specimens is less diagnostic since nontoxic or toxin A positive-toxin B negative strains are prevalent in Japan. Reliable laboratory tests for ETBF-associated childhood diarrhea are not established yet although ETBF can be proved by polymerase chain reaction for detection of the enterotoxin gene.

Animals↗
PubMed1998

Interleukin-1 receptor antagonist inhibits transient increase of plasma corticosterone in the initial phase of trimethyltin-induced hippocampal necrosis.

The temporal increase of plasma corticosterone (CORT) levels at 3 or 4 days after a single oral administration of trimethyltin (TMT) was suppressed by intracerebroventricular administration of the interleukin-1 receptor antagonist (IL-1ra). On the other hand, glutamate receptor antagonist (MK801) did not affect the TMT-induced CORT level increase. These results indicate that this transient activation of the hypothalamo-pituitary-adrenocortical axis in TMT-treated rats may be in part attributable to the neuroendocrine effects of IL-1 produced by microglia.

Administration, Oral↗