Biomedical subjects

I Kato

Publications and source records attributed to I Kato.

At least 19 recordsLinked to original sources

PubMed1992

Genomic structure of the human caldesmon gene.

The high molecular weight caldesmon (h-CaD) is predominantly expressed in smooth muscles, whereas the low molecular weight caldesmon (l-CaD) is widely distributed in nonmuscle tissues and cells. The changes in CaD isoform expression are closely correlated with the phenotypic modulation of smooth muscle cells. During a search for isoform diversity of human CaDs, l-CaD cDNAs were cloned from HeLa S3 cells. HeLa l-CaD I is composed of 558 amino acids, whereas 26 amino acids (residues 202-227 for HeLa l-CaD I) are deleted in HeLa l-CaD II. The short amino-terminal sequence of HeLa l-CaDs is different from that of fibroblast (WI-38) l-CaD II and human aorta h-CaD. We have also identified WI-38 l-CaD I, which contains a 26-amino acid insertion relative to WI-38 l-CaD II. To reveal the molecular events of the expressional regulation of the CaD isoforms, the genomic structure of the human CaD gene was determined. The human CaD gene is composed of 14 exons and was mapped to a single locus, 7q33-q34. The 26-amino acid insertion is encoded in exon 4 and is specifically spliced in the mRNAs for both h-CaD and l-CaDs I. Exon 3 is the exon that encodes the central repeating domain specific to h-CaD (residues 208-436) together with the common domain in all CaD (residues 73-207 for h-CaD and WI-38 l-CaDs, and residues 68-201 for HeLa l-CaDs). The regulation of h- and l-CaD expression is thought to depend on selection of the two 5' splice sites within exon 3. Thus, the change in expression between l-CaD and h-CaD might be caused by this splicing pathway.

Alternative Splicing↗

PubMed1992

An enzyme releasing lacto-N-biose from oligosaccharides.

alpha-L-Fucosidase (alpha-L-fucoside fucohydrolase; EC 3.2.1.51) preparations from Streptomyces sp. 142 were found to contain an enzyme specific for lacto-N-biosidic (Gal beta 1-3GlcNAc beta 1-) linkages (type 1 structure) in oligosaccharides. The enzyme preparation, which was eluted after alpha-fucosidase from a CM-Sepharose column, contained some alpha-fucosidase activity but was free from other glycosidases and proteases. Substrate specificity studies with oligosaccharides labeled with 2-aminopyridine showed that the enzyme specifically hydrolyzed lacto-N-tetraose (Gal beta 1-3GlcNAc beta 1-3Gal beta 1-4Glc) but did not hydrolyze lacto-N-neotetraose (Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4Glc), lacto-N-triose, sialyl lacto-N-tetraose, lacto-N-fucopentaose I, II, or III, asialo-GM1 tetrasaccharide, or poly-N-acetyllactosamine. Structural analysis of the enzyme digest of the N-acetyllactosamine type of triantennary sugar chain with type 1 structure showed that lacto-N-biose (Gal beta 1-3GlcNAc) and the N-acetyllactosamine type of biantennary sugar chain were produced. Thus this enzyme was tentatively named lacto-N-biosidase, because it hydrolyzes oligosaccharides containing a type 1 structure at the nonreducing terminus and produces lacto-N-biose.

Carbohydrate Sequence↗

PubMed1992

A monoclonal antibody-based enzyme immunoassay for human GMP-140/P-selectin.

Two hybridoma cell lines producing monoclonal antibodies WGA-1 and PL7-6, reactive only with thrombin-stimulated human platelet have been established. Both these antibodies were investigated for their specific reactivity against GMP-140, based on the amino acid composition analysis of immunopurified antigen and N terminal amino acid sequencing of its protease fragments. A two-site enzyme immunoassay for quantification of human GMP-140 was developed using WGA-1 monoclonal antibody immobilized on 96-well microplates and horseradish peroxidase-labeled PL7-6 monoclonal antibody as detector. The assay was able to measure GMP-140 in serum and plasma with a sensitivity of about 5 ng/ml and a precision better than 10%. This assay will be useful for the detection of GMP-140 derived from platelets or endothelium in biological fluids and tissue extracts.

Amino Acid Sequence↗

PubMed1992

Molecular cloning and nucleotide sequence of leukocidin F-component gene (lukF) from methicillin resistant Staphylococcus aureus.

A lukF gene encoding F-component of Staphylococcal leukocidin from methicillin resistant Staphylococcus aureus (MRSA) was cloned. The nucleotide sequence of lukF gene was determined. The sequence data have revealed an open reading frame, which encodes a polypeptide with 323 amino acid residues. Inspection of the amino acid sequence deduced from nucleotide sequence of lukF and that from F-component of leukocidin from S. aureus V8 clarified that pre-matured F-component contains a typical signal peptide at the NH2 terminus and ATG starting codon for pre-matured F-component was present one base downstream to the TGA which is translation termination codon for S-component of leukocidin [A. Rahman et al. (1991) Biochem. Biophys. Res. Commun. 181, 138-144]. The nucleotide sequence of 5'-flanking region of lukF showed the presence of the consensus sequence of ribosome binding site in the internal region of the structural gene of S-component. The lukF was transcribed in the same direction as that of lukS. No Pribnow box can be discerned in the intercistronic region between the lukS and lukF genes. The amino acid sequence homology between S- and F-components was 31%. F-component was expressed in Escherichia coli DH5 alpha harboring plasmid pFRK92 which contained lukF gene.

Amino Acid Sequence↗

PubMed1992

A prospective study of gastric and duodenal ulcer and its relation to smoking, alcohol, and diet.

The effects of environmental exposures on the development of gastric and duodenal ulcers were investigated in a prospective study of 7,624 American men of Japanese ancestry in Hawaii. After 149,291 person-years of observation, there were 280 incident cases of gastric ulcer and 149 incident cases of duodenal ulcer. The risk of both gastric and duodenal ulcers progressively increased with increasing pack-years of cigarette smoking. In contrast, alcohol intake was not associated with either type of ulcer. The risk of gastric ulcer was positively associated with the use of table salt/soy sauce, but there was no association with the consumption of other oriental foods. The risk of duodenal ulcer was inversely associated with western style diet around 1940 and with bread intake of two or more servings per day. The authors did not find any protective or adverse effect of milk and fruit consumption on peptic ulcer risk.

Age Factors↗

PubMed1992

Cloning and expression of the HpaI restriction-modification genes.

The genes from Haemophilus parainfluenzae encoding the HpaI restriction-modification system were cloned and expressed in Escherichia coli. From the DNA sequence, we predicted the HpaI endonuclease (R.HpaI) to have 254 amino acid residues (Mr 29,630) and the HpaI methyltransferase (M.HpaI) to have 314 amino acid residues (37,390). The R.HpaI and M.HpaI genes overlapped by 16 base pairs on the chromosomal DNA. The genes had the same orientation. The clone, named E. coli HB101-HPA2, overproduced R.HpaI. R.HpaI activity from the clone was 100-fold that from H. parainfluenzae. The amino acid sequence of M.HpaI was compared with those of other type II methyltransferases.

Amino Acid Sequence↗

PubMed1992

Construction and characterization of a fusion protein with epidermal growth factor and the cell-binding domain of fibronectin.

An efficient expression system was constructed for C-EGF, a fusion protein made of a fragment of the cell-binding domain of human fibronectin (FN) bound with epidermal growth factor (EGF). C-EGF was produced in Escherichia coli HB101 cells carrying the recombinant plasmid pCE102 as inclusion bodies, which were solubilized and refolded after purification. C-EGF had both cell-adhesive and EGF activities, so it might be more effective than EGF in therapeutic applications. This fusion system would be useful for the construction of a recombinant drug delivery system for cells that have fibronectin receptors (integrins).

Cell Adhesion↗

PubMed1992

'boxA'-like sequence between the 16 S/23 S spacer in rRNA operon of mycoplasmas.

We have found that a boxA-like sequence is conserved in the 16 S and 23 S rRNA intergenic spacer regions of mycoplasmas, and that it always locates on loop regions of the hypothetical secondary stem-loop structures. A nucleotide sequence similar to the '-10' box of prokaryotic promoters was identified at upstream sites of the boxA-like sequence in the 16 S/23 S spacer regions. These structures may represent an internal promoter between the 16 S and 23 S rRNA genes in mycoplasmas.

Base Sequence↗

PubMed1992

Epoxyeicosatrienoic acid stimulates ADP-ribosylation of a 52 kDa protein in rat liver cytosol.

In rat liver cytosol, rapid ADP-ribosylation of a 52 kDa protein by endogenous ADP-ribosyltransferase(s) was observed. This ADP-ribosylation was stimulated dose-dependently by 14,15-epoxyeicosatrienoic acid (14,15-EET), one of the metabolites of arachidonic acid by NADPH-dependent cytochrome P-450 mono-oxygenase. This stimulatory effect required the presence of GTP or its non-hydrolysable analogues, guanosine 5'-[beta gamma-imido]triphosphate or guanosine 5'-[gamma-thio]triphosphate. Of four regioisomeric EETs, 14,15-EET was the most potent. No stimulatory effect was observed with addition of 14,15-dihydroxyeicosatrienoic acid, a stable metabolite of 14,15-EET. The 52 kDa protein was not ADP-ribosylated by cholera toxin A subunit and pertussis toxin, and was not recognized by anti-Gs alpha and anti-Gi alpha antibodies. However, the 52 kDa protein could be photoaffinity-labelled with 8-azidoguanosine 5'-[alpha-32P]triphosphate. These results suggest that the 52 kDa protein is neither Gs nor Gi, though it may have a GTP-binding site. These results contribute to the understanding of the role of mono-oxygenase metabolites of arachidonic acid in intracellular signal transduction.

8,11,14-Eicosatrienoic Acid↗

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↗