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Biomedical subjects

I Kato

Publications and source records attributed to I Kato.

At least 253 records · Page 14Linked to original sources
PubMed1995

A nested case-control study of mammographic patterns, breast volume, and breast cancer (New York City, NY, United States).

The relations of Wolfe mammographic patterns, quantitative mammographic densities, and mammographically estimated breast size to breast cancer risk were investigated prospectively in a case-control study nested in the New York University Women's Health Study, a cohort of 14,291 women in New York City, NY (United States). The archived mammograms of 197 breast cancer cases who were identified during the first 5.5 years of the study and of 521 individually matched controls from the same cohort were retrieved and classified according to Wolfe parenchymal patterns and mammographic densities by two expert radiologists. Breast size and volume were estimated on the mammogram's cranio-caudal projection. In both premenopausal and postmenopausal subjects, the risk of breast cancer increased progressively with increasing density and percent density area. A significantly increased risk was found also for Wolfe pattern DY in premenopausal women and P2 pattern in postmenopausal subjects. In premenopausal women, mammographically determined breast volume and breast height also were associated positively with breast cancer risk. Although the results of the present study confirmed that mammographic parenchymal patterns and densities were important predictors of breast cancer risk, their practical use in screening seems limited due to the high prevalence of high risk patterns.

Adult↗
PubMed1995

Inter-observer variation in cytological and histological diagnoses of cervical neoplasia and its epidemiologic implication.

Inter-observer variation in cytohistological diagnosis was assessed for 1506 cervical smears and 883 histological slides from four case-control studies on cervical neoplasia. The kappa statistic among a panel of three cytopathologists was highest for diagnosis of invasive cancer (0.70 for cytology and 0.74 for histology), followed by normal/inflammatory in cytology (0.68) and CIN III in histology (0.58). There was also nearly perfect agreement between the final panel diagnoses and the original diagnoses made by local cytopathologists, except for those of CIN III. Inter-observer variation in diagnosis for CIN III was inversely associated with age, number of children (in histology) and sexual activity (in cytology). However, the odds ratios for CIN III calculated by each cytopathologist's diagnosis were not different from each other for any etiologic factor. These results indicate that the diagnoses of invasive cancer and of normal/inflammatory changes are highly reproducible and that the inter-observer variation does not have much impact on the etiologic risk estimates.

Adult↗
PubMed1995

Fibronectin and 130-kDa molecule complex mimics snake venom botrocetin-like structure potentially modulating association between von Willebrand factor and vascular vessel wall.

We established seven hybridomas secreting monoclonal antibodies (MoAbs) against the venom from Bothrops jararaca. Six of them were demonstrated to specifically recognize botrocetin, a venom protein which binds with von Willebrand factor (vWf) and induces platelet agglutination. Two of them, BCT4-3 and BCT115-2 MoAbs, could significantly inhibit botrocetin binding with plasma vWf. BCT4-3 could react slightly with a monolayer of human endothelial cells (ECs), and BCT4-3 binding to ECs was drastically enhanced by the coexistence of human plasma in a dose-dependent manner, indicating that a biological modulator structurally resembling botrocetin is created initially on the EC surface complexed with some plasma proteins. Botrocetin-like components could be immuno-purified only by immobilized BCT4-3, but not by the other immobilized MoAbs, from umbilical vein extracts. Interestingly, the immunoisolated materials were identified to consist essentially of fibronectin (Fn) and a 130 kDa molecule, and this complex bound to vWf in the extracts. Depletion of Fn from plasma decreased BCT4-3 binding to ECs. The epitope of BCT4-3 expressed on the endothelial surface, comprising plasma Fn and the coisolated 130 kDa molecule, is proposed to be a physiological modulator structurally mimicking botrocetin, and essentially supporting vWf-binding to injured endothelium and subsequently to circulating platelets.

Antibodies, Monoclonal↗
PubMed1995

Complete covalent structure of porcine liver acylamino acid-releasing enzyme and identification of its active site serine residue.

The complete covalent structure of porcine liver acylamino acid-releasing enzyme (AARE) [EC3.4.19.1], which catalyzes the hydrolysis of an N-terminally acylated peptide to release an N-acylamino acid, has been established. On basis of the amino acid sequence deduced from the cDNA sequence of porcine liver AARE [Mitta, M. et al. (1989) J. Biochem. 106, 548-555], sequence determination has been achieved by automated Edman degradation of peptides generated by chemical or enzymatic cleavages of the reduced and S-carboxymethylated protein. Ion-spray mass spectrometry was also successfully used to confirm the amino acid sequences of the peptides determined above and to elucidate both the N-terminal blocking group and the status of half-cystine residues of this protein. The protein consists of 732 amino acid residues, and the N-terminal methionine residue is blocked by an acetyl group. All of 18 half-cystine residues of this protein were proved to exist as cysteine residues. A serine residue reactive with diisopropyl fluorophosphate (DFP) was also identified as Ser587 by preparation of the AARE labeled with tritiated DFP followed by isolation and sequence analysis of a radioactive peptide obtained from its endoproteinase Asp-N digest.

Amino Acid Sequence↗
PubMed1995

The amino acid sequence required for 5' --> 3' exonuclease activity of Bacillus caldotenax DNA polymerase.

We studied the 5' --> 3' exonuclease activity of Bacillus caldotenax DNA polymerase by site-directed mutagenesis. Among seven mutants constructed, two mutant DNA polymerases with an amino acid substitution of Gly184 --> Asp or Gly192 --> Asp were confirmed to be deficient in this exonuclease. The two positions corresponded to those of the Escherichia coli DNA polymerase I mutants defective in 5' --> 3' exonuclease, polA480ex and polA214. These results provide experimental support for the proposed amino acid sequence essential for the 5' --> 3' exonuclease activity associated with eubacterial polymerase I-like DNA polymerases (family A), including E.coli and Thermus aquaticus.

Bacillus↗
PubMed1995

Extracellular antigens of Actinobacillus actinomycetemcomitans Y4 in severe alveolar bone loss patients studied by two-dimensional electrophoresis and western blots.

The human immune response to extracellular substances (ES) from Actinobacillus actinomycetemcomitans Y4 were analyzed. Twenty-nine periodontal patients with generalized severe alveolar bone loss and 13 healthy volunteers were examined for serum IgG antibody titers against ES. Among the patients, 17 had higher antibody titers than healthy individuals (high-titer patients) but the remainder (low-titer patients) did not. Two-dimensional electrophoresis (2DE) and Western blots demonstrated that two proteins (40 and 37 kDa) and three smeared substances reacted with IgGs from high-titer patients, but not with IgGs from healthy volunteers. The low-molecular-mass smear at the acid side reacted with over 90% of all patients. This smear reacted with anti-A. actinomycetemcomitans lipopolysaccharide (LPS) monoclonal antibody which recognized LPS from each A. actinomycetemcomitans serotype. The high molecular mass smear at the acid side might be serotype-specific O-antigens of LPS. Another high molecular mass smear which located from the alkaline to the neutral side reacted with anti-serotype-b-specific capsular polysaccharide monoclonal antibody. Moreover, the 40- and 37-kDa proteins reacted with this anti-capsular polysaccharide antibody. This results suggested that 40- and 37-kDa proteins which reacted with 100% or 88% of high-titer patients might be glycoproteins linked with capsular polysaccharide.

Actinobacillus Infections↗
PubMed1995

Identification and possible function of cathepsin G in gingival crevicular fluid from chronic adult periodontitis patients and from experimental gingivitis subjects.

The levels of cathepsin G in gingival crevicular fluid (GCF) from chronic adult periodontitis patients and experimental gingivitis subjects were determined both by activity measurement using N-benzoyl-(DL)-phenylalanine-2-naphthyl ester as a substrate and by enzyme immunoassay using anti-human cathepsin G IgG. The activity level of cathepsin G in GCF of both periodontitis and experimental gingivitis has no significant correlation with all measured clinical parameters. Western immunoblotting using antibodies specific for cathepsin G or alpha 1-proteinase inhibitor revealed that the difficulty in demonstrating the association of its activity with the severity of these diseases was due largely to formation of the enzyme-inhibitor complexes. By contrast, statistically significant positive correlation was found between cathepsin G content in GCF of periodontitis, which was determined by enzyme immunoassay, and such clinical parameters as the GCF volume, the gingival index and probing depth. The increased cathepsin G content with increasing severity of periodontal inflammation was markedly diminished by the initial treatment. Although no significant activity was detectable in GCF of experimental gingivitis, a rapid increase of the immunoreactive cathepsin G was found in GCF at 3-5 d after refraining from oral hygiene measures, which rapidly decreased by 10 d. The progressively increased cathepsin G between 10th and 21st d rapidly decreased by cleaning of the teeth. The results indicate that cathepsin G is involved in the host's defensive mechanism against the invasion of etiologic microbes and/or the development of either periodontitis or gingivitis.

Adult↗
PubMed1995

Detection of antigenic proteins in Porphyromonas gingivalis using two-dimensional electrophoresis and western blots.

Using two-dimensional (2D) electrophoresis and western blot assay, we analyzed antigenic proteins in Porphyromonas gingivalis uniquely recognized by antibodies in sera of periodontitis subjects. Proteins in the total membrane fraction of P. gingivalis 381 were resolved into at least 70 protein spots by 2D electrophoresis. In the gel stained with silver, the substance around 47 kDa protein on the acidic side (at an isoelectric point of about 4.5) was stained as a smear. Antigenic substances were characterized using purified IgGs from sera of 16 adult periodontitis (AP), 19 rapidly progressive periodontitis (RPP) and 14 periodontally healthy volunteers. Western blots demonstrated that 75 kDa protein reacted with IgGs from 75% of AP patients (p < 0.001), the antigenic substance around acidic 47 kDa protein reacted with IgGs from 81.3% of AP (p < 0.01) and 68.4% of RPP patients (p < 0.01) and the acidic 47 kDa protein reacted with 87.5% of AP (p < 0.01) and 78.9% of RPP patients (p < 0.01). The reaction frequency was significantly different from that of the healthy volunteers. Also 51 kDa and 41 kDa proteins reacted with 47 and 43 of 49 IgG samples, respectively. The substance around acidic 47 kDa protein reacted with mouse antiserum to P. gingivalis-LPS. After treatment with pronase or heat, the antigenic reactions disappeared not only from the proteins, but also from the area around the acidic 47 kDa protein. When the fraction was digested with lipase, the antigenic reaction of the area decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Histological study of lectin binding in regenerated rat junctional epithelium.

We investigated the expression of carbohydrate residues in regenerated junctional epithelium (JE) cells histopathologically with lectin staining to clarify the mechanisms responsible for the changes in their expression in JE cells derived from residual oral epithelium. Curettage and root planing procedures were performed on the buccal gingival sulci of rat first lower molars, and JE and connective tissues were completely removed. The mandibles were resected after 12 h and 1, 2, 3, 4, 5, 7, 10 and 14 days, fixed with paraformaldehyde, decalcified with EDTA and embedded in paraffin. Serial sections were stained histochemically with four kinds of lectins (PNA, DBA, GS I, UEA I) to clarify the expression patterns of carbohydrate residues in regenerating epithelium. No binding of PNA or DBA was observed even when the regenerating epithelium was attached to the root surface, and they showed the same negative reactions as the basal cells of oral gingival epithelium (OGE). Positive reactions were, however, observed on the more stratified regenerating epithelium along the root surface. Positive reactions with GS I and negative reactions with UEA I were observed throughout the regeneration process, and these were the same as those observed in the basal cells of OGE. Therefore, we concluded that the basal cells and regenerated epithelium derived from OGE expressed the same carbohydrate residues. Furthermore, the expression of carbohydrate residues, one of the characteristics of JE, was related not only to the attachment to the tooth surface but also to changes of cell shape and cytoskeleton with stratification along the root surface.

Animals↗
PubMed1995

The hyperthermophilic archaeon Pyrodictium occultum has two alpha-like DNA polymerases.

We cloned two genes encoding DNA polymerases from the hyperthermophilic archaeon Pyrodictium occultum. The deduced primary structures of the two gene products have several amino acid sequences which are conserved in the alpha-like (family B) DNA polymerases. Both genes were expressed in Escherichia coli, and highly purified gene products, DNA polymerases I and II (pol I and pol II), were biochemically characterized. Both DNA polymerase activities were heat stable, but only pol II was sensitive to aphidicolin. Both pol I and pol II have associated 5'-->3' and 3'-->5' exonuclease activities. In addition, these DNA polymerases have higher affinity to single-primed single-stranded DNA than to activated DNA; even their primer extension abilities by themselves were very weak. A comparison of the complete amino acid sequences of pol I and pol II with two alpha-like DNA polymerases from yeast cells showed that both pol I and pol II were more similar to yeast DNA polymerase III (ypol III) than to yeast DNA polymerase II (ypol II), in particular in the regions from exo II to exo III and from motif A to motif C. However, comparisons region by region of each polymerase showed that pol I was similar to ypol II and pol II was similar to ypol III from motif C to the C terminus. In contrast, pol I and pol II were similar to ypol III and ypol II, respectively, in the region from exo III to motif A. These findings suggest that both enzymes from P. occultum play a role in the replication of the genomic DNA of this organism and, furthermore, that the study of DNA replication in this thermophilic archaeon may lead to an understanding of the prototypical mechanism of eukaryotic DNA replication.

Amino Acid Sequence↗
PubMed1995

The impact of alcohol and hypertension on stroke incidence in a general Japanese population. The Hisayama Study.

BACKGROUND AND PURPOSE: The relationship between alcohol intake and stroke has been inconsistent in previous studies. We examined the separate and combined effects of drinking habits and hypertension on stroke incidence in a prospective survey of a general Japanese population. METHODS: A total of 1621 stroke-free Hisayama residents aged 40 years or older were classified by their alcohol intake into nondrinkers, light drinkers (< 34 g of ethanol per day), and heavy drinkers (> or = 34 g of ethanol per day) and followed up prospectively for 26 years from 1961. RESULTS: During the follow-up period, cerebral infarction developed in 244 subjects and cerebral hemorrhage in 60. For men, the incidence of cerebral hemorrhage increased significantly with rising alcohol consumption. In contrast, the incidence of cerebral infarction was slightly lower in light drinkers than in nondrinkers, while it increased significantly in heavy drinkers compared with light drinkers. Female drinkers had a lower incidence of cerebral infarction but a slightly higher incidence of cerebral hemorrhage than nondrinkers, as did male light drinkers. Among the hypertensive subjects, the age- and sex-adjusted relative risk of cerebral hemorrhage was significantly elevated in heavy drinkers versus abstainers (3.13; 95% confidence interval [CI], 1.08 to 9.10), but the increase was not significant for light drinkers. In contrast, the relative risk did not significantly increase for normotensive light and heavy drinkers. Compared with hypertensive light drinkers, the relative risk of cerebral infarction significantly increased in hypertensive heavy drinkers (1.96; 95% CI, 1.08 to 3.57) but remained unchanged in normotensive heavy drinkers. Significant associations between alcohol intake and stroke were substantially the same even after controlling for other risk factors in multivariate analysis. CONCLUSIONS: Among hypertensive individuals, heavy alcohol consumption leads to a significant increase in the risk of cerebral hemorrhage, suggesting a synergistic effect of alcohol and hypertension, while light alcohol consumption significantly reduces the risk of cerebral infarction.

Adult↗
PubMed1995

Silent cerebral infarction in a community-based autopsy series in Japan. The Hisayama Study.

BACKGROUND AND PURPOSE: The purpose of this study was to assess the prevalence and characteristics of silent cerebral infarction in a population-based consecutive autopsy series of residents of Hisayama, Kyushu, Japan. METHODS: Autopsy records, cerebral pathological findings, and clinical charts of 966 Hisayama residents recorded during the 26 years from 1961 to 1987 were examined (autopsy rate, 82.4%). The subjects were divided into three groups: those with both clinically apparent strokes and pathologically verified cerebral infarcts (stroke group), those having pathological evidence of cerebral infarction in the brain but without clinical stroke episodes (silent infarction group), and those with neither infarction nor stroke episode (noninfarction group). Risk factors and brain pathology in the three groups were compared. RESULTS: Silent cerebral infarction was found in 12.9% of the 966 subjects who had undergone autopsy, and its frequency increased with age. The subjects with silent infarcts were older, had higher systolic or diastolic blood pressure, and had atrial fibrillation more frequently than subjects in the noninfarction group. There were no significant differences in the locations of infarcts between the stroke and silent infarction groups, although infarcts tended to be located in the deeper area of the brain in the latter. The number and size of infarcts were smaller in the silent infarction group than in the stroke group. CONCLUSIONS: Diastolic blood pressure and atrial fibrillation appear to be strong predictors of silent cerebral infarction in the Japanese general population. Stroke becomes clinically apparent as infarct volume increases.

Adult↗
PubMed1995

Incidence and risk factors of vascular dementia and Alzheimer's disease in a defined elderly Japanese population: the Hisayama Study.

We followed 828 nondemented residents of Hisayama Town, Kyushu, Japan, aged 65 years or older (88.3% of the elderly population) for 7 years starting in 1985 in order to determine the type-specific incidence of dementia and its risk factors in the general Japanese population. Only two subjects were lost to the follow-up, during which period 103 subjects developed dementia. Morphologic examination of the brains of 89 subjects (86.4%) was made by autopsy or CT. We made the initial diagnosis of dementia based on the DSM-III-R criteria, with the diagnoses of vascular dementia (VD) being based on the NINDS-AIREN criteria and Alzheimer's disease (AD) on the NINCDS-ADRDA criteria. The incidence of VD and AD increased with age for both sexes. The age-adjusted total incidence (per 1,000 person-years) of dementia was 19.3 for men and 20.9 for women. The corresponding rates for VD were 12.2 for men and 9.0 for women, and for AD, 5.1 for men and 10.9 for women. Among the VD subjects whose brain morphology we examined, the most frequent type of stroke was multiple lacunar infarcts (42%), but half these subjects lacked a stroke episode in their histories. Multivariate analysis showed that age, prior stroke episodes, systolic blood pressure, and alcohol consumption were significant independent risk factors for the occurrence of VD. In contrast, age and a low score on Hasegawa's dementia scale were significant risk factors for AD, and physical activity was a significant preventive factor for AD.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

A non-alpha-like DNA polymerase from the hyperthermophilic archaeon Pyrococcus furiosus.

We identified a DNA polymerase with properties that differed from those of alpha-like DNA polymerase (Pol I), in Pyrococcus furiosus, a hyperthermophilic archaeon. The novel DNA polymerase (Pol II) was partially purified and characterized. The DNA polymerizing activity of Pol II was relatively sensitive to dideoxythymidine-triphosphate (ddTTP) and it was inhibited by N-ethylmaleimide, but not by aphidicolin. Activity staining gel electrophoresis showed that the DNA polymerizing activity was derived from a polypeptide with a molecular weight of 130000 on sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. The DNA elongation ability of Pol II using a natural DNA template was much lower than that of Pol I from this organism and DNA synthesis of Pol II seems to be non-processive.

Aphidicolin↗
PubMed1995

A novel repetitive sequence from Mycoplasma hyopneumoniae.

We have isolated a novel repetitive DNA element from Mycoplasma hyopneumoniae strain VPP11, the entire structure of which is distinct from those of prokaryotic transposons, insertion sequences or eukaryotic retroposons reported. Southern blot hybridization experiments indicate that at least eight copies of this element locate on the M. hyopneumoniae genome. The size of this repetitive sequence is 4,193 bp which includes 270- and 272-bp direct long terminal repeats at each terminus. The internal domain of this element defines three open reading frames.

Animals↗
PubMed1995

Visually guided eye movements in patients with Wallenberg's syndrome.

To determine the lesions and the lateralization in patients with Wallenberg's syndrome, visually-guided eye movements were quantitatively analysed and these findings were compared with a lesioned site as revealed by magnetic resonance imaging (MRI). The 8 patients could be clearly classified into two subgroups based on the functional test of eye movements. In 4 patients, optokinetic nystagmus (OKN), pursuit eye movements and fixation-suppression of caloric nystagmus (FS), utilizing the slow phase velocity as a parameter, were impaired toward the lesioned side in the medulla. In the remaining 4 patients, OKN and pursuit eye movements were impaired toward the side contralateral to the lesion, whereas FS toward the lesioned side, indicating a lesion affecting not only the medulla but also the inferior peduncle and/or the cerebellum. Therefore, the functional visually-guided eye movements can provide a useful test battery with which to detect the lesion site in Wallenberg's syndrome.

Angiography↗
PubMed1995

Indications and results of gentamycin injection into the middle ear of patients with meniére's disease.

Forty-six cases in whom endolymphatic drainage surgery was performed between 1986 and 1992 were followed up for more than 2 years. The results of numerical values (1985 AAOHNS) revealed complete control of definite spells in 26 cases; substantial control of definite spells in 18 cases; limited control of definite spells in 1 case; and insignificant control of definite spells in 1 case. Hence, endolymphatic drainage surgery for Meniére's disease was effective. There are, however, cases who cannot be operated on because of old age or underlying diseases. In these, we injected gentamycin sulfates mixed with prednisolone through a ventilated tube into the middle ear. The results for gentamycin injection based on numerical values showed complete control of definite spells in 12 cases; and substantial control of definite spells in 7 cases. Our treatment of choice for Meniére's disease is endolymphatic drainage surgery which resulted in 96% control of vertigo. In patients for whom operation has failed, in old patients and in those with hearing impairment more than 50 dB, gentamycin injection into the middle ear has proved to be an effective procedure to control vertigo attacks.

Adult↗