Biomedical subjects

K Sakata

Publications and source records attributed to K Sakata.

At least 379 records · Page 21Linked to original sources

PubMed1990

Purification of an active gelatinase from collagen fiber fraction of granulation tissue in rats.

Gelatinase was extracted at 60 degrees C from the collagen fiber-rich fraction of granulation tissue induced by carrageenin in rats. A large part of the extracted gelatinase was unbound to Zn-chelating Sepharose. The unbound gelatinase gave a single band corresponding to a molecular mass of 57 kDa on SDS-substrate PAGE, but showed a much higher molecular mass (greater than 200 kDa) on Sephadex G-150 gel filtration. In addition, that unbound fraction contained gelatin fragments was revealed by SDS-PAGE. When the unbound fraction of Zn-chelating Sepharose was incubated at 37 degrees C, the gelatin fragments disappeared and the apparent molecular mass of gelatinase in gel filtration decreased. This gelatin degradation of the unbound fraction was enhanced by treatment with a 4-aminophenylmercuric acetate (APMA). The results suggest that the gelatinase is bound to gelatin fragments in the unbound fraction. After the treatment with APMA, the gelatinase was purified to to homogeneity; the purified gelatinase gave a single band corresponding to a molecular mass of 57 or 67 kDa on SDS-PAGE under nonreducing or reducing conditions, respectively. The purified gelatinase is a metalloproteinase, and extensively degraded gelatin, but showed no proteolytic activity toward alpha-casein or types I and IV collagens. The results suggest that the 67-kDa active gelatinase is bound to collagen fibers and plays an important role in a rapid degradation of collagen fibers in granulation tissue.

Animals↗

PubMed1990

SPECT imaging with Tl-201 and Ga-67 in myocardial sarcoidosis.

Two patients with myocardial sarcoidosis are presented, both of whom underwent SPECT imaging with Tl-201 and Ga-67. The first had Ga-67 myocardial uptake with a Tl-201 defect, which disappeared with corticosteroid therapy. The second had multiple Tl-201 defects without Ga-67 uptake, which persisted despite corticosteroid therapy. Therefore, the combination of Tl-201 and Ga-67 imaging may be useful for recognizing myocardial sarcoidosis and for predicting the response to corticosteroid therapy.

Adrenal Cortex Hormones↗

PubMed1990

Changes in plasminogen activator inhibitor 1 and tissue-type plasminogen activator during exercise in patients with coronary artery disease.

As depressed fibrinolysis is implicated in the pathogenesis of coronary artery disease, we have studied the activation of fibrinolysis during maximal, symptom-limited exercise in a group of 68 men. After exercise they were divided, according to their coronary angiography and exercise 201Tl emission computed tomography results, into three groups. Group 1: persons with normal exercise 201Tl emission computed tomography results and no underlying diseases who served as controls; group 2: patients with coronary artery disease without exercise-induced myocardial ischemia, and group 3: patients with coronary artery disease with transient, exercise-induced myocardial ischemia. Before and at peak exercise we measured the plasminogen activator activity (PAA) in the euglobulin fraction of plasma by an amidolytic method and the concentrations of tissue plasminogen activator (t-PA), activator-inhibitor complex - plasminogen activator inhibitor 1 (PAI-1) complexed with t-PA - and total PAI-1 by enzyme immunoassay. The concentration of free PAI-1 in plasma was calculated by subtraction of the concentration of activator-inhibitor complex from that of total PAI-1. Under basal conditions, group 3 had significantly higher free and total PAI-1 levels than group 1. There were no statistically significant differences between the three groups in PAA, t-PA, and activator-inhibitor complex levels. At peak exercise, group 1 showed the highest release of t-PA accompanied with highest increases in PAA as well as in activator-inhibitor complex, the proportion of released t-PA antigen not bound to PAI-1 being highest in group 1. Free PAI-1 decreased significantly, but there were no differences between individual groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1990

An epidemiological study of the influence of sweets intake and toothbrushing on dental caries among children in Japan.

The study was designed to determine the influence of confectionery and beverages intake and of toothbrushing on infant dental caries. The participants were 700 three year old Japanese children from an urban area near Tokyo. The prevalence of caries in those who frequently consumed confectionery and beverages was higher than the prevalence in those who did not take them. However, the prevalence in children with a habit of toothbrushing did not differ from that of those without the habit. This study shows that restricting consumption of confectionery and beverages may be effective in preventing dental caries; however, encouragement of toothbrushing may not be effective in limiting dental caries progression.

Beverages↗

PubMed1990

[Clinical results of sequential and "Y" grafting with the internal mammary artery].

One hundred and sixty-five patients (125 men, 40 women; age ranged from 40 to 81 years), underwent coronary artery bypass grafting in the 3 years period from 1986 to 1988. The internal mammary artery (IMA) was applied to 125 patients (75.8%). The sequential left IMA grafting to the left anterior descending coronary artery (LAD) and the diagonal branch (Dg) was performed in 9 out of 125 patients. In 3 of 9 patients, the right IMA was simultaneously grafted to the obtuse marginal branch (OM). In situ bilateral IMAs grafting to the LAD and Dg or LAD and OM were used in 13 patients. In three patients, "Y" grafting (the free right IMA was anastomosed to the side of the in situ left IMA) was performed for LAD and Dg. Eighty-one of 82 IMA grafts (99%) were patent about 1 month after operation. Three patients (1.8%) died during hospitalization, one from Low Output Syndrome, two from cerebral infarction. Perioperative complication included myocardial infarction in 5 (3.0%), cerebral infarction in 10 (6.0%). We concluded that the IMA could be applied in multivessel grafting as well as single vessel grafting in severe diffuse coronary artery disease in the Japanese, and the early patency was good even in the sequential and "Y" grafting.

Adult↗

PubMed1990

[Drug information in recent 5 volumes of the Year Book of Dentistry].

The Year Book of Dentistry appears annually, providing a review of dental articles. We surveyed the abstracts of the recent 5 volumes of the Year Book of Dentistry, from 1985 to 1989. Two hundred and eighty articles were abstracted in each volume, divided into about 13 categories. The proportion of abstracts concerned with drugs and drug therapies (here termed drug information) was almost 20% in all volumes. Most of the drug information appeared under the heading "Oral Medicine and Oral Pathology" (63%). The original articles for the abstracts were from many journals, but 70% of the drug information articles were from JADA, Oral Surgery, and 10 other journals. The classification of the drugs in the drug information were: drugs for dental treatment, antibacterials, antiinflammatories, hemostatics, anesthetics, and others. Oral manifestations of systemic diseases or side effects of drugs used for these diseases were also abstracted. There were numerous articles of systemic diseases, due to dental treatments, including infective, hematologic diseases.

Abstracting and Indexing↗

PubMed1990

[A proposal for evaluation charts on the health services for the aged by municipalities].

A method to evaluate health services for the aged enforced by municipalities (cities, towns and villages) based on the health service law for the aged is proposed. The evaluation method is to draw three visual charts which compare the quantities, qualities and effects of health services for the aged. Software for personal computers for producing the evaluation charts by using periodically collected health services data on a municipality basis is developed. Examples of the charts of two municipalities (a city and a town) are shown and the validity of the charts are discussed.

Aged↗

PubMed1990

[Therapeutic effects by implantable infusion pump for hepatic malignant tumors].

Chemotherapy and chemoembolization using implantable infusion pump were performed in fifteen cases of hepatocellular carcinoma (HCC) and one case of cholangioma. The following results were obtained; (1) Complete response (CR) was obtained in two cases (12.5%) and partial response (PR) in three cases (18.8%) with HCC. (2) Tumor thrombus in the portal vein disappeared in two of four cases with HCC. (3) The followup period ranged from 54 to 768 days and administration from one to 33 times. These results suggest that good therapeutic effects and quality of life can be obtained by implantable drug delivery system.

Adult↗

PubMed1990

[A case of anomalous right pulmonary venous drainage to high segment of superior vena cava with intact atrial septum--surgical repair by cavoatrioplasty avoiding injury to the sinoatrial node and its feeding artery].

Surgical repair of anomalous right pulmonary venous drainage to the high segment of the superior vena cava (SVC) with intact atrial septum in a 5-year-old girl by cavoatrioplasty avoiding injury to the sinoatrial (SA) node and its feeding artery is described. The procedure was composed of #1: an oblique incision at the anterior wall of SVC above the anomalous right pulmonary veins (ARPVs) and closure of the lower end of the SVC, making the lower segment of SVC the ARPV channel, #2: a fan-shaped incision at the base of the right atrial (RA) appendage and suturing the cephalad flap over a created atrial septal defect, diverting the ARPV flow through the SVC into the left atrium, and #3: reconstruction of continuity between the cephalad end of the SVC and the RA by suturing the RA appendage flap over the lower segment of SVC. Pulmonary valvotomy was also done for concomitant pulmonary stenosis. Postoperative course of the patient was excellent, with constant normal sinus rhythm. Angiography one month after operation showed no stenosis of the SVC and pulmonary venous pathways. The method reported here was considered to have following advantages: It employs simple and short incisions, avoids injury to the SA node its feeding artery, and achieves wide and nonobstructive pathways of both SVC and pulmonary venous return without using foreign material.

Child, Preschool↗

PubMed1990

[A case of intimal dissection of the left internal mammary artery grafting].

A 73-year-old man underwent reoperation using the in situ left internal mammary artery (IMA) because of the stenosis of the vein graft to the left anterior descending artery (LAD). The patient recovered free from angina but angiography performed 1 month after operation revealed the dissection of intima of the left IMA. Use of the IMA in coronary artery bypass grafting (CABG) is now generally accepted as the optimal method of myocardial revascuralization and the use of the left IMA to the LAD has become a routine procedure in our CABG surgery. However, because the IMA wall is friable and disruption occurs easily, especially in the elder, much care should be taken during mobilization of the IMA.

Aged↗

PubMed1990

[Shortest route for in situ left thoracic artery to left anterior descending coronary artery].

For coronary artery bypass grafting, the internal thoracic artery (ITA) graft carries a greater long-term patency and a decreased need for reoperation when compared with the saphenous vein graft. However, the number and length of ITAs limit their use. In an effort to extend the use of the ITA and to improve patency, we evaluated the shorter course from the left ITA (LITA) origin to the left anterior descending coronary artery (LAD). We compared the distance using the conventional route over the lung (20 patients) with that using the newly-devised route medial to the lung and through the pericardial incision (20 patients). The distance using the route medial to the lung and through the pericardial incision was 12.6 +/- 1.4 cm (mean +/- SD), which was shorter compared with 15.1 +/- 1.1 cm of the route over the lung (p less than 0.01). And also the route medial to the lung and through the pericardial incision could avoid the danger of strectching or kinking by the inflated left lung. From these results, we concluded that the use of the route medial to the lung and through the pericardial incision was better method of extending the use of the in situ LITA to LAD.

Coronary Artery Bypass↗

PubMed1990

[Examination of the rectosphincteric reflex by means of endoscopic electrical stimulation. A new device].

An endoscopic electrical stimulation method (the new method) for the examination of the rectosphincteric reflex was devised to overcome difficulties attributable to the manometric method using balloon stimulation. Safety of the electrical stimulation under the conditions used routinely, was confirmed symptomatically and histologically. It was found that the optimal parameters of electrical stimulation to obtain the recto-sphincteric reflex were: 1 ms, 20 Hz, 5 to 7mA, and for 3 sec. The degree of the reflex relaxation became less and the time lag of the response to the stimulation became longer, as the distance of the stimulation site from the anal verge was increased. These relationships were significant. In the cases which received anterior resection of the rectum, the rectosphincteric reflex was examined using the new method. In 12 of 39 cases the recto-sphincteric reflex was induced by stimulation at the oral side of the anastomosis. In all of them the reflex was observed at 9 or more months postoperatively. Incidence of postoperative reflex appearance tended to be higher after end-to-end anastomosis than after side-to-end anastomosis. In two cases which received Duhamel-Okamoto's operation and in one which received Soave-Denda's operation, it was possible to analyze the relationship between the stimulating site and presence or absence of the reflex-like phenomenon.

Adult↗

PubMed1989

Selective potentiation of lymphocyte-derived macrophage chemotactic factor release in complete Freund's adjuvant-treated guinea pigs.

Dinitrophenol (DNP)-ovalbumin(OA)-induced tissue macrophage reaction in sensitized guinea pigs is enhanced by treatment with complete Freund's adjuvant (CFA). The enhancement of the reaction may be due to the increased production of a T-lymphocyte-derived macrophage chemotactic factor (LDMCF) because treatment of animals with CFA potentiates antigen- and concanavalin A(ConA)-induced release of LDMCF activity from spleen cells of the CFA-treated animals in vitro. This potentiating effect by CFA seems to be ascribed to the release of an adherent-cell-derived soluble factor from the CFA-treated animals. The adherent cell-derived factor, LDMCF-potentiating factor (LDMCF-PF), preferentially potentiates the release of LDMCF activity but not of eosinophil chemotactic activity from antigen- or Con-A-stimulated T lymphocytes. Protein synthesis is required for release of LDMCF-PF. Molecular weight of LDMCF-PF activity is assumed to be about 10,000-20,000. LDMCF-PF activity is sensitive to trypsin, to neuraminidase, and also to alkalinity at pH 11, suggesting that LDMCF-PF is a glycoprotein. The present study provides one explanation for the enhanced macrophage reaction in delayed-type hypersensitivity reactions.

Animals↗

PubMed1989

Mechanism of arrhythmias induced by palmitylcarnitine in guinea pig papillary muscle.

Long chain acyl carnitines, intermediates of free fatty acid metabolism, have been implicated in malignant arrhythmias occurring during myocardial ischaemia. To investigate the mechanism of arrhythmia induced by these compounds the electrophysiological effects of palmitylcarnitine (30, 100 and 300 mumol.litre-1) on guinea pig papillary muscles was examined using the microelectrode technique. Palmitylcarnitine caused a time and concentration dependent shortening of action potential duration, with an increase in both developed and resting tension. After attaining the peak value of developed tension, delayed afterdepolarisations and/or aftercontractions were observed in three out of eight muscles on exposure to 100 mumol.litre-1 palmitylcarnitine and in all 13 muscles on exposure to 300 mumol.litre-1, while arrhythmia occurred in one out of eight muscles and in seven out of 13 muscles during these exposures. The amplitude and the coupling interval of delayed afterdepolarisations were dependent on basic cycle length. Delayed afterdepolarisations, aftercontractions and arrhythmias were completely abolished by ryanodine (1 mumol.litre-1). Though low Ca2+ (0.1 mmol.litre-1) abolished these activities, verapamil (4 and 10 mumol.litre-1) did not suppress them. Palmitylcarnitine (300 mumol.litre-1) shortened action potential duration to the same degree during metabolic block of either oxidative phosphorylation or glycolysis as it did in muscles exposed to oxygenated Krebs solution. Under these conditions, delayed afterdepolarisation and/or aftercontractions appeared in all muscles. We conclude that palmitylcarnitine could cause Ca2+ overload and trigger activity due to delayed afterdepolarisations and could act on the cell membrane independently of cardiac metabolism. We suggest that palmitylcarnitine is a factor in arrhythmogenesis during myocardial ischaemia.

Action Potentials↗

PubMed1989

The role of the fibrinolytic system in acute myocardial infarction after a normal exercise test.

A 67-year-old man had an acute myocardial infarction with thrombosis in the left anterior descending artery shortly after normal exercise. We were able to measure the fibrinolytic components in this patient just prior to his developing acute myocardial infarction as well as during convalescence. In this case, marked increase in total plasminogen activator inhibitor-1 (PAI-1) antigen, mainly due to free PAI-1 antigen, was observed in basal conditions before the onset of acute myocardial infarction. On the appearance of ischaemia, plasminogen activator activity was suppressed, probably due to decreased tissue plasminogen activator antigen release and increased PAI activity, compared with that during convalescence. This suggests that some patients with coronary artery disease who have a high level of free PAI-1 antigen in basal conditions may have a strong tendency to develop acute myocardial infarction, due to further impaired fibrinolysis on the induction of ischaemia.

Acute Disease↗

PubMed1989

Purification and characterization of exudate gelatinases in the chronic-phase of carrageenin-induced inflammation in rats.

Gelatinases have been purified from the exudate in the chronic-phase (day 7) of carrageenin-induced inflammation in rats. The day-7 exudate gelatinases gave two peaks on Sephadex G-150 gel filtration, the initial step of the purification. The molecular weights of the gelatinases corresponding to the two peaks were about 300 kDa (HMW fraction) and about 110 kDa (LMW fraction), respectively. The gelatinase in the HMW fraction has been purified to homogeneity; the purified gelatinase gave a single band corresponding to a molecular weight of 57 kDa on both SDS-polyacrylamide gel electrophoresis (PAGE) and SDS-gelatin PAGE. On the other hand, the gelatinase purified from the LMW fraction was found to consist of three species, with molecular weights of 66, 64, and 57 kDa, as judged on SDS-gelatin PAGE. Granulation tissue-derived fibroblasts in culture mainly produced the 64-kDa species, which was converted to a 57-kDa species on treatment with 4-amino-phenylmercuric acetate, while rat macrophages and polymorphonuclear leukocytes mainly secreted the 96-kDa species. These results suggest that exudate gelatinases are largely produced by fibroblasts in granulation tissue and that they bind to exudate proteins, resulting in the formation of complexes with molecular weights of about 300 kDa and about 110 kDa. The gelatinases purified from the HMW and LMW fractions are metalloproteinases, as judged from the results of inhibitor experiments. Both the gelatinases degraded gelatin, but showed to proteolytic activity toward alpha-casein or type I collagen. Type IV collagen was degraded at 35 degrees C by the gelatinases purified from the LMW fraction but not by that from the HMW fraction.

Animals↗

PubMed1989

Patent ductus arteriosus with Eisenmenger's syndrome detected by first-pass study.

The case of a 20-year-old man with patent ductus arteriosus complicated with Eisenmenger's syndrome is described. Radionuclide angiocardiography characterized the abnormal pattern of blood flow through the central circulation to establish a diagnosis of patent ductus arteriosus with a significant right-to-left shunt, which had not been indicated by other clinical findings.

Adult↗

PubMed1989

Effects of endothelin on the mechanical activity and cytosolic calcium level of various types of smooth muscle.

1. Effects of porcine/human endothelin (endothelin-1), a novel vasoconstrictor peptide, on various smooth muscles were examined. 2. In rat aorta, endothelin (1 pM-30nM) induced contraction in a concentration-dependent manner. Removal of endothelium shifted the concentration-response curve to the left. When added during the sustained contraction induced by 0.1 microM noradrenaline, endothelin (1 nM) induced a relaxation that was inhibited by removing endothelium or by methylene blue. 3. In rat aorta without endothelium, endothelin (1-30 nM) increased cytosolic Ca2+ level [( Ca2+]cyt) followed by contraction. Endothelin induced less contraction than high K+ at a given [Ca2+] cyt when the concentration of endothelin was lower (1-3nm) and/or during the early phase of the contraction (less than 10 min). In contrast, endothelin induced a greater contraction than KCl after prolonged exposure to high concentrations (greater than 10 nM). 4. The increase in [Ca2+]cyt due to endothelin was strongly inhibited by 10 microM verapamil or 0.3 microM nicardipine although muscle contraction was only partially inhibited. 5.In Ca2+ -free solution, endothelin (30 nM) induced a transient increase in [Ca2+] cyt and a slow increase in muscle tension. After a prolonged incubation in Ca2+-free solution, endothelin (30 nM) still induced a slow increase in tension without changing [Ca2+]cyt. This contraction was inhibited by 1 microM sodium nitropusside or 10 microM forskolin. 6. In canine trachea and guinea-pig uterus, endothelin (30 nM) induced sustained contraction with an increase in [Ca2+]cyt. In the absence of external Ca2+, endothelin (30 nM) induced a sustained contraction in canine trachea without changing [Ca2+]cyt. In guinea-pig vas deferens, taenia caeci and ileal longitudinal muscle, endothelin induced small increases in [Ca2+]cyt and tension. 7. In permeabilized smooth muscles, endothelin (30 nM) did not change the muscle tone. 8. These results suggest that endothelin acts on the endothelium and increases the synthesis or release of endothelin-derived relaxing factor (EDRF). These results also suggest that endothelin acts directly on smooth muscle and increases [Ca2+]cyt by releasing Ca2+ from sites and increasing Ca2+ influx through the verapamil- and 1,4-dihydropyridine-sensitive pathway. Endothelin seems to decrease Ca2+ -sensitivity of contractile elements at lower concentrations and/or during the early phase of the contraction, whereas it increases Ca2+ -sensitivity at higher concentrations during the sustained phase of the contraction. Furthermore, endothelin induces a contraction that is not dependent on [Ca2+]cyt.

Animals↗