Biomedical subjects

I Kato

Publications and source records attributed to I Kato.

At least 361 records · Page 20Linked to original sources

PubMed1992

Prospective study of the association of alcohol with cancer of the upper aerodigestive tract and other sites.

The association of alcohol consumption with cancers of the upper aerodigestive tract, hepato-biliary-pancreatic system, urogenital organs (except for prostate), and lymphohematopoietic tissue was evaluated in a prospective study of 6,701 American men of Japanese ancestry living in Hawaii. Compared with cancer-free subjects, subjects who subsequently developed cancers of the upper aerodigestive tract (oral-pharynx, esophagus, and larynx), liver, biliary tract, and lymphohematopoietic tissue consumed significantly larger amounts of total alcohol--mainly in the form of beer. Subjects who developed oral-pharyngeal and esophageal cancer also consumed larger amounts of wine and spirits. Because the upper aerodigestive tract cancers were associated positively with cigarette smoking, age-adjusted relative risks (RR) were calculated, based on joint exposure to cigarette smoking and heavy alcohol intake (greater than or equal to 30 ml/day) in this population. A markedly increased risk was observed among subjects who were both heavy alcohol drinkers and smokers (RR = 17.3, 95 percent confidence interval [CI] = 6.7-44.2), compared with subjects who who did not smoke and did not drink heavily. The risk for these cancers also was increased among heavy alcohol drinkers who were nonsmokers (RR = 8.6, CI = 2.1-36.0).

Aged↗

PubMed1992

Congenital cerebral venous dysgenesis. Decreased cerebral blood flow in deep cerebral regions revealed by SPECT.

This report describes a rare case of primary cerebral venous dysgenesis in a 3-year-old child with development retardation. Angiography resulted in nonvisualization not only of deep cerebral veins but also of superficial cerebral veins. In computed tomography and in magnetic resonance imaging the collateral venous circulation appeared as a strange configuration in the pineal region. Single photon emission computed tomography using N-isopropyl-p-[I-123]-iodoamphetamine revealed decreased regional cerebral blood flow in the basal ganglia and thalamus, but cerebral infarction was not detected in the area. These features indicate that in this case, dysgenesis of deep cerebral veins, which probably occurred during prenatal life, had caused hypoperfusion in the deep cerebral regions.

Carotid Arteries↗

PubMed1992

Ion-spray mass spectrometric analysis of glycosaminoglycan oligosaccharides.

Oligosaccharides from hyaluronic acid and chondroitin 6-sulfate were prepared by digestion with testicular hyaluronidase and separated according to their degree of polymerization by gel-permeation chromatography. These materials were successively analyzed by negative-mode ion-spray mass spectrometry with an atmospheric-pressure ion source. An ion-spray interface was used to produce ions via the ion evaporation process, producing mass spectra containing a series of molecular species carrying multiple charges. Using two adjacent multiply charged molecular ions, the exact molecular weights up to the tetradecasaccharide were calculated with a precision of +/- 1 dalton. This type of mass spectrometry was also demonstrated to be feasible for the analysis of mixtures of oligosaccharides, including tetra-, hexa-, octa- and decasaccharides, from hyaluronic acid or chondroitin 6-sulfate without separation. Ion-spray mass spectrometry was thus shown to be applicable to the structural analysis of oligosaccharides from glycosaminoglycans.

Animals↗

PubMed1992

Prospective study of clinical gallbladder disease and its association with obesity, physical activity, and other factors.

The association of anthropometric measurements, serum tests, and life-style factors with the risk of clinical gallbladder disease was investigated in a prospective study of 7831 American men of Japanese ancestry in Hawaii. After 152,831 person-years of observation, 471 incident cases of gallbladder disease were diagnosed by histology or radiology. There was an increase in risk of gallbladder disease with a progressive increase in body mass index, height, pack-years of cigarette smoking, and diastolic blood pressure. There was a decrease in risk with an increase in physical activity, after controlling for the effect of other variables. There was also an inverse association with total caloric intake that could be related to dietary restriction in obese subjects or to the limitations of the 24-hr diet history. Serum cholesterol levels and the intake of total fat were not related to clinical gallbladder disease in this cohort.

Age Factors↗

PubMed1992

A case-control study of breast cancer among Japanese women: with special reference to family history and reproductive and dietary factors.

To study the effects of family history and reproductive, anthropometric, and dietary factors on the risk of breast cancer among low risk populations, we conducted a hospital-based case-control study involving 908 patients with breast cancer and their matched controls, in Japan. A positive family history of breast cancer significantly increased the risk of breast cancer (odds ratio = 1.52, 95% confidence interval: 1.14-2.03). The risk further increased with increasing number of family members affected. Obesity, single marital status, fewer births, a late childbirth, and less consumption of green-yellow vegetables and dairy products were also associated with an increased risk of breast cancer. These associations were independent in multivariate analyses. There was no increase in risk associated with consumption of high fat foods. When analyzed by menopausal status, the association with family history of breast cancer, especially in the first degree of relatives, was more evident for premenopausal breast cancer. The associations with obesity and lower consumption of dairy products were more pronounced for postmenopausal breast cancer, while those with lower parity and single marital status were stronger for premenopausal breast cancer.

Adult↗

PubMed1992

Clinical evaluation of tissue plasminogen activator (t-PA) levels in patients with liver diseases.

Tissue plasminogen activator (t-PA) levels in plasma or serum were studied in 416 patients with liver diseases: acute hepatitis (AH, n = 30); fulminant hepatitis (FH, n = 36); chronic inactive hepatitis (CIH, n = 57); chronic active hepatitis (CAH, n = 39); compensated liver cirrhosis (cLC, n = 78); decompensated liver cirrhosis (dLC, n = 84); hepatocellular carcinoma (HCC, n = 64); advanced hepatocellular carcinoma (aHCC, n = 28); and compared with that of a control group (n = 106) of healthy subjects. The t-PA levels showed significant increase in patients with AH, FH, CAH, cLC, dLC and HCC, compared with normal controls. The abnormal rates in t-PA levels (higher than 8.3 ng/ml) for each type of liver diseases were 86.1% in FH, 46.2% in CAH, 50% in cLC, 85.7% in dLC, 67.2% in HCC, and 89.3% in aHCC. t-PA levels tended to be higher in more advanced liver diseases. t-PA levels significantly correlated positively with plasminogen activator inhibitor (PAI-1) in AH, cLC, dLC, HCC and aHCC, and negatively with plasmin alpha 1-plasmin inhibitor complex (PIC), plasminogen (Plg), FDP, AT III and alpha 2-plasmin inhibitor (alpha 2-PI) in dLC, prothrombin time (PT) and fibrinogen (Fbg) in HCC. t-PA levels in patients with FH, CAH and dLC were significantly higher than those in patients with AH, CIH and cLC, respectively. Moreover, the changes of t-PA levels in the clinical courses of various liver diseases revealed that t-PA levels increased sensitively with progression of liver diseases or in advanced liver diseases.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomarkers↗

PubMed1992

Analysis of oligosaccharides by on-line high-performance liquid chromatography and ion-spray mass spectrometry.

Oligosaccharides were analyzed by a combination of high-performance liquid chromatography (HPLC) and mass spectrometry (MS). First, oligosaccharides labeled with 2-aminopyridine were studied to see if they could be analyzed by MS under the conditions used for separation by HPLC. Pyridylamino (PA)-oligosaccharides could be analyzed under these conditions, although the mass spectra were affected. Then, liquid chromatography-mass spectrometry was used to analyze a PA-oligosaccharide mixture derived from human immunoglobulin G. The PA-oligosaccharides were separated on a reversed-phase column and mass-analyzed directly. The observed molecular weights were close to or identical to those expected from the structures, which were estimated from the elution position on HPLC. This method is rapid and simple, as the mass spectrometer can give the accurate molecular weight of each PA-oligosaccharide in one chromatography run, even if the HPLC separation is incomplete. This method can be used to extend the so-called two-dimensional mapping of PA-oligosaccharides. The structure can be studied in greater detail by tandem MS.

Carbohydrate Conformation↗

PubMed1992

An in vitro model for assessing muscle irritation of antibiotics using rat primary cultured skeletal muscle fibers.

This study examined the possibility of using rat primary cultured skeletal muscle fiber to estimate the muscle irritation of antibiotics. The cells were exposed to cefaloridine (CER), cefazolin sodium (CEZ), flomoxef sodium (FMOX), cefamandole sodium (CMD), latamoxef sodium (LMOX), or cefalotin sodium (CET) at concentrations of 0 (control), 31.25, 62.5, 125, and 250 mg/ml in culture medium for 1 hr on Day 11 of culture. Cellular creatine kinase (CK) activity was measured as an indication of cell injury. The concentration of the antibiotic, at which CK activity decreased to 50% of the control (depletion concentration 50%, DC50), was utilized as an index of cytotoxicity. DC50s of CER, CEZ, FMOX, CMD, LMOX, and CET were estimated to be 406.7, 311.1, 211.6, 132.7, 114.2, and 56.5 mg/ml, respectively. There was a good correlation between DC50 obtained in the present in vitro test and the irritation volume in the in vivo test. These results suggest that the in vitro system using rat primary cultured skeletal muscle fibers is a useful alternative model for in vivo rabbit study to evaluate muscle irritation.

Animals↗

PubMed1992

Dependence of peak dP/dt and mean ejection rate on load and effect of inotropic agents on the relationship between peak dP/dt and left ventricular developed pressure--assessed in the isolated working rat heart and cardiac muscles.

To examine the effects of preload (mean left atrial pressure) and afterload on two so-called "contractility indices" and the effects of inotropic agents (isoproterenol and calcium) on the relationship between left ventricular developed pressure and peak dP/dt when afterload was increased, we used a modified working rat heart preparation (perfused with Krebs-Henseleit solution bubbled with a 95% O2 -5% CO2 gas mixture at 37 degrees C). The atrium was stimulated at a rate of 240/min. An increase in preload from 5 to 15 mmHg caused an increase in peak dP/dt from 1,711 +/- 293 mmHg/s to 1,971 +/- 387 mmHg/s (p less than 0.001, n = 15), and an increase in the mean systolic ejection rate from 1.28 +/- 0.31 ml/s to 2.74 +/- 0.80 ml/s (p less than 0.001). An increase in afterload (left ventricular developed pressure) from 66 to 97 mmHg produced by elevating aortic pressure caused an increase in peak dP/dt from 1,829 +/- 222 mmHg/s to 2,449 +/- 254 mmHg/s (p less than 0.001, n = 7), and a decrease in the mean systolic ejection rate from 2.12 +/- 0.36 ml/s to 1.95 +/- 0.33 ml/s (p less than 0.001). Studies using isolated rat papillary muscles ruled out the contribution of an increase in myocardial perfusion to the increase in peak dP/dt, since the maximum rate of rise in tension (dT/dt) increased with an increase in afterload during afterloaded isotonic contraction. Peak dP/dt showed a linear relationship to left ventricular developed pressure when the latter was increased by elevating the aortic reservoir and then clamping the aortic outflow tube (n = 8).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Aphidicolin inhibits DNA polymerizing activity but not nucleolytic activity of Escherichia coli DNA polymerase II.

We have purified the DNA polymerase II of Escherichia coli from the recombinant strain carrying the plasmid which encodes the polB gene. We confirmed that the purified protein, of molecular weight 90,000, possesses a 3'----5' exonuclease activity in addition to DNA polymerizing activity in a single polypeptide. Its DNA polymerizing activity was sensitive to the drug aphidicoline, which is a specific and direct inhibitor of the alpha-like DNA polymerases including eukaryotic replicative DNA polymerases. Aphidicolin had no detectable effect on the 3'----5' exonuclease activity. The inhibition by aphidicolin on the polymerizing activity of polymerase II was competitive with respect to dNTP and uncompetitive with respect to template DNA. This mode of action is the same as that on eukaryotic DNA polymerase alpha. The apparent Ki value calculated from Lineweaver-Burk plots was 55.6 microM.

Aphidicolin↗

PubMed1992

Prospective study of serum cholesterol and site-specific cancers.

From 1965 to 1968, 7716 Japanese-American men were examined and tested for serum cholesterol. After 22 years, 1380 incident cancer cases were identified. Of the site-specific cancers, only colon cancer cases had a significantly lower mean serum cholesterol value than that of noncases (213.0 mg/dl vs 219.0 mg/dl). When the study subjects were separated into either a low, middle or high group, based on their serum cholesterol values, there was a significant inverse trend for cases of oral/pharyngeal/esophageal cancer combined. The association was present for cases diagnosed within 10 years of examination (p = 0.012), but not for cases diagnosed after 10 years. This suggests that the inverse association is due to the metabolic effects of undiagnosed oral/pharyngeal/esophageal cancer upon serum cholesterol levels. These results are discussed in relation to other studies on serum cholesterol.

Aged↗

PubMed1992

Determinants of sex hormone levels in men as useful indices in hormone-related disorders.

Because the determinants of serum sex hormone levels in men have been infrequently studied, we investigated the relation of several personal characteristics to serum levels of testosterone (T), dihydrotestosterone (DHT), estrone (E1), estradiol (E2) and sex hormone-binding globulin (SHBG) among 98 Japanese American men in Hawaii, aged 52-74. The SHBG levels and T/(E1 + E2) ratios decreased progressively with increasing body mass index. The SHBG levels were also inversely associated with hematocrit levels. Serum androgen and estrogen levels did not correlate with smoking, alcohol intake, serum cholesterol, serum uric acid and blood pressure. Some of the associations observed in the present study may be implicated in the etiology of hormone-related neoplasms in men.

Aged↗

PubMed1992

Urinary laminin fragments as a tumour marker potentially reflecting basement membrane destruction.

The presence of soluble laminin fragments in urine of healthy subjects, patients with diabetes, and patients with tumours was studied using sandwich immunoenzymometric assay technique. The form of urinary laminin (ULN) fragments was dramatically different from that of intact laminin, so ULN could be detected only by using monoclonal antibodies. Mean levels of ULN in lung tumour were significantly higher (171 micrograms gram-1 creatinine) than those in healthy subjects, patients, with diabetes, patients with stomach tumour, and patients with colon tumour (respectively 91, 92, 77 and 53 micrograms gram-1 creatinine). Immunopurified ULN fragments showed an apparent molecular mass of 42 KD on electrophoresis. This fragment was recognised as being derived from the N-terminal region of laminin B2 chain, because the N-terminal residues of ULN were found to be completely homologous to B2 chain. These data suggested that ULN was almost all fragmented, consisted mainly of N-terminal domain of the B2 chain, and was suspected of a tumour-associated protein fragments probably derived from basement membrane degraded proteolytically by tumour cells. ULN, increased in tumour patients, could be a potential clinical marker for monitoring the turnover of basement membrane in tumours.

Amino Acid Sequence↗

PubMed1992

Engineering of artificial cell adhesion proteins by grafting the Arg-Gly-Asp cell adhesive signal to a calpastatin segment.

A new artificial cell adhesive protein was engineered by grafting the Arg-Gly-Asp (RGD) sequence, the minimal recognition signal of fibronectin for interaction with integrins, to a calpastatin segment by in vitro mutagenesis. The mutagenized protein showed cell adhesive activity in addition to calpain inhibitory activity. The RGD signal grafted to the calpastatin segment was recognized by the vitronectin receptor but not by the fibronectin receptor.

Amino Acid Sequence↗

PubMed1992

The primary structure of porcine aminoacylase 1 deduced from cDNA sequence.

A cDNA encoding the complete amino acid sequence of aminoacylase 1 (N-acylamino acid aminohydrolase, ACY-1) [EC 3.5.1.14], a dimeric metalloprotein having two Zn2+ in the molecule, which catalyzes the deacylation of N-acylated L-amino acids except L-aspartic acid, has been isolated from porcine kidney lambda gt10 cDNA library and sequenced. From sequence analysis of the cDNA and the N- and C-terminal amino acid analyses of the purified protein, it is deduced that porcine kidney ACY-1 consists of two identical subunits (M(r) 45,260), each of which consists of a single chain of 406 amino acids with acetylalanine at the N-terminus. A cDNA encoding porcine liver ACY-1 was also cloned. The amino acid sequence deduced from the nucleotide sequence of the cDNA from porcine liver was identical to that deduced for porcine kidney ACY-1. Northern blot analysis suggested that ACY-1 is more highly expressed in kidney than in liver. Comparison of the amino acid sequence of porcine ACY-1 with those of other Zn2+-binding metalloenzymes showed no significant homologies in either the overall sequence or the consensus sequences for the metal binding sites. This indicates that ACY-1 is a new type of metalloprotein.

Amidohydrolases↗

PubMed1992

Nucleotide sequence of the arginine deiminase gene of Mycoplasma hominis.

The arginine deiminase gene of Mycoplasma hominis was amplified by the polymerase chain reaction, and its entire nucleotide sequence was determined. This gene consists of 1227 base pairs encoding 409 amino acids, and has 35.2% guanine plus cytosine content. Nucleotide sequence homologies of the arginine deiminase gene between M. hominis and M. arginini, and between M. hominis and M. orale were 82.1 and 80.8%, respectively, suggesting that this gene is highly conserved among arginine-utilizing Mycoplasma species.

Amino Acid Sequence↗

PubMed1992

Comparison of secretory acid proteinases from Candida tropicalis, C. parapsilosis and C. albicans.

Acid proteinases secreted by Candida tropicalis and C. parapsilosis were newly isolated. Their physico-chemical and enzymatic properties of molecular weight, pH stability, isoelectric points, specific activity, and N-terminal amino acid sequences were determined and compared with those of a C. albicans acid proteinase. The two acid proteinases secreted by C. parapsilosis were found to be new enzymes in their molecular weights. The acid proteinases from C. tropicalis and C. parapsilosis showed lower activity at neutral pH, less resistance to neutral and alkaline pH than that from C. albicans, and a half or a third of the specific activity of the C. albicans enzyme. These differences seemed to be associated with the difference of pathogenesis between Candida species. Of the 31 N-terminal amino acids, the enzymes of these three Candida species revealed 12 homologous amino acids.

Amino Acid Sequence↗

PubMed1992

cDNA cloning of an aspartic proteinase secreted by Candida albicans.

cDNA of an aspartic proteinase secreted by Candida albicans No. 114 was isolated using the polymerase chain reaction (PCR). The primary structure of the enzyme was deduced from the nucleotide sequence of the cDNA and compared with the structures of Saccharomyces cerevisiae proteinase A and vacuolar aspartyl proteinase of C. albicans. The mature aspartic proteinase consisted of 341 amino acid residues, and was 17.6 and 15.3% identical with the proteinase A and the aspartyl proteinase, respectively. Two active aspartic acid sites and the amino acids near those sites were conserved in the aspartic proteinase. We also showed that there is another gene of aspartic proteinase than that of strain ATCC10231 reported by Hube et al (J. Med. Vet. Mycol. 29 (1991)) in the same C. albicans genome, both in that strain and in No. 114.

Amino Acid Sequence↗