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Biomedical subjects

H Yoshihara

Publications and source records attributed to H Yoshihara.

At least 109 records · Page 6Linked to original sources
PubMed1988

[Extracorporeal shock-wave lithotripsy for radiolucent calculi in the upper urinary tract].

Eight years have passed since extracorporeal shock-wave lithotripsy (ESWL) was used clinically for the first time, and now its usefulness is recognized all over the world. At first, variable cases were considered to be contra-indicative, one of which was the radiolucent calculi. This time for two cases of the radiolucent calculi we performed ESWL under retrograde pyelography. Using this technique, we brought the filling defect of RP into the focus of the shock waves. The stones were effectively disintegrated and these patients became stone-free in five weeks.

Humans↗
PubMed1987

Urea synthesis from ammonia in periportal and pericentral regions of the liver lobule. Effect of oxygen.

Rates of urea synthesis were determined in periportal and pericentral regions of the liver lobule in perfused liver from fed, phenobarbital-treated rats by measuring the extra O2 consumed upon infusion of NH4Cl with miniature O2 electrodes and from decreases in NADPH fluorescence detected with micro-light-guides. Urea synthesis by the perfused rat liver supplemented with lactate (5 mM), ornithine (2 mM) and methionine sulfoximine (0.15 mM), an inhibitor of glutamine synthetase, was stimulated by stepwise infusion of NH4Cl at doses ranging from 0.24 mM to 3.0 mM. A good correlation (r = 0.92) between decreases in NADPH fluorescence and urea production was observed when the NH4Cl concentration was increased. Sublobular rates of O2 uptake were determined by placing miniature oxygen electrodes on periportal or pericentral regions of the lobule on the liver surface, stopping the flow and measuring decreases in oxygen tension. From such measurements local rates of O2 uptake were calculated in the presence and absence of NH4Cl and local rates of urea synthesis were calculated from the extra O2 consumed in the presence of NH4Cl and the stoichiometry between O2 uptake and urea formation. Rates of urea synthesis were also estimated from the fractional decrease in NADPH fluorescence, caused by NH4Cl infusion in each region, measured with micro-light-guides and the rate of urea synthesis by the whole organ. When perfusion was in the anterograde direction, maximal rates of urea synthesis, calculated from changes in fluorescence, were 177 +/- 31 mumol g-1 h-1 and 61 +/- 24 mumol g-1 h-1 in periportal and pericentral regions, respectively. When perfusion was in the retrograde direction, however, rates were 76 +/- 23 mumol g-1 h-1 in periportal areas and 152 +/- 19 mumol g-1 h-1 in pericentral regions. During perfusion in the anterograde direction, urea synthesis, calculated by changes in O2 uptake, was 307 +/- 76 mumol g-1 h-1 and 72 +/- 34 mumol g-1 h-1 in periportal and pericentral regions, respectively. When perfusion was in the retrograde direction, urea was synthesized at rates of 54 +/- 17 mumol g-1 h-1 and 387 +/- 99 mumol g-1 h-1 in periportal and pericentral regions, respectively. Thus, maximal rates of urea synthesis were dependent upon the direction of perfusion. In addition, rates of urea synthesis were elevated dramatically in periportal regions when the flow rate per gram liver was increased (e.g. 307 versus 177 mumol g-1 h-1).(ABSTRACT TRUNCATED AT 400 WORDS)

Ammonia↗
PubMed1987

Menadione causes selective toxicity to periportal regions of the liver lobule.

Infusion of increasing concentrations (0.2-1 mM) of the quinone, menadione, caused step-wise increases in oxygen uptake in perfused livers from fasted rats presumably due to oxygen-dependent redox cycling. Maximal increases in oxygen uptake of about 40 mumol/g/h were observed with 0.8 to 1.0 mM menadione. This increase in oxygen uptake was confined to periportal areas of the liver lobule suggesting that redox cycling due to menadione occurs exclusively in cells localized around the portal triad. After 60 min of infusion of menadione (1 mM), lactate dehydrogenase was released from the liver at rates between 60 to 70 U/g/h. Under these conditions, trypan blue was taken up by virtually all hepatocytes in periportal regions of the liver lobule. In contrast, dye was not taken up by cells in pericentral areas. It is concluded that menadione is selectively toxic to hepatocytes located in oxygen-rich periportal regions of the liver lobule.

Animals↗
PubMed1987

Involvement of calmodulin-calcium complex in regulation of O2 uptake in regions of the liver lobule.

In livers from phenobarbital sodium-treated rats, O2 uptake was two- to three-fold higher in periportal than in pericentral regions during perfusions in the anterograde direction confirming previous studies. The purpose of this study is to evaluate the role of calmodulin in the regulation of local rates of O2 uptake. O2 uptake was inhibited up to 80% in a dose-dependent fashion by the calmodulin inhibitor, W-7 (I0.5 = 50-60 microM). In isolated mitochondria, however, W-7 had minimal effects on state 3 and 4 rates of O2 uptake. Moreover, fructose increased O2 uptake in perfused liver to a similar extent in the presence and absence of W-7, indicating that a direct effect of W-7 on mitochondria in the perfused liver can be ruled out. In perfusions in the anterograde direction, W-7 (100 microM) decreased O2 uptake from 129 to 45 mumol . g-1 . h-1 in upstream periportal regions of the liver lobule and from 47 to 36 mumol . g-1 . h-1 in downstream pericentral areas. When perfusion was in retrograde direction, however, O2 uptake was twofold higher in upstream pericentral areas. Under these conditions, W-7 decreased O2 uptake from 160 to 59 mumol . g-1 . h-1 in upstream pericentral areas and from 58 to 43 mumol . g-1 . h-1 in downstream periportal regions. Thus W-7 decreased O2 uptake predominantly in upstream regions of liver lobule irrespective of the direction of flow. Increases in O2 uptake caused by epinephrine (0.1 microM) and angiotensin II (5 nM), hormones that increase intracellular Ca2+, were blocked totally by W-7.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

[Clinical evaluation of ofloxacin against complicated urinary tract infections].

Clinical efficacy of ofloxacin (OFLX) against complicated urinary tract infections was examined in 20 patients. OFLX was administrated orally at a dose of 200 mg, three times (daily 600 mg) for 14 to 102 days. The overall clinical efficacy was rated excellent in 8 cases (40%), moderate in 7 cases (35%) and poor in 5 cases (25%) with a total efficacy of 75%. Bacteriological efficacy, 17 out of 24 strains (70.8%) isolated were eradicated after OFLX administration. The strains that appeared after OFLX treatment were P. cepacia and Candida sp. No severe side effects were found in these patients.

Administration, Oral↗
PubMed1986

Acid stable trypsin inhibitor in bile.

Acid stable trypsin inhibitor having the same antigenicity as urinary trypsin inhibitor was first identified in the bile of patients with malignant tumors (biliary tract carcinoma or pancreas head carcinoma) and gallstones. Bile trypsin inhibitor from malignant tumor patients was partially purified by DEAE cellulose ion exchange column chromatography. Two molecular forms of the inhibitor were identified. The main form had a molecular weight of about 86,000 and the minor one a molecular weight of 31,000 as determined by gel filtration. Using isoelectric focussing, the larger molecular form gave a pI value of 2.0 and the smaller form, a pI value of 5.1. The isolated larger form migrated on the slightly cationic side of human serum albumin by analytical polyacrylamide gel electrophoresis. The larger form reacted and fused with anti-urinary trypsin inhibitor serum and strongly inhibited trypsin, partially inhibited chymotrypsin and plasmin, but did not inhibit urokinase. The clinical significance of acid stable trypsin inhibitor is discussed.

Bile↗
PubMed1986

Side effects of extracorporeal shock-wave exposure in patients treated by extracorporeal shock-wave lithotripsy for upper urinary tract stone.

The side effects of shock-wave exposure on patients treated by extracorporeal shock-wave lithotripsy were analyzed by measuring chemical substances including cell-escaped enzymes in the blood and urine. Free hemoglobin, glutamic oxaloacetic transaminase (GOT) and lactate dehydrogenase (LDH) increased as a function of shock-wave count. Total bilirubin, GOT and LDH reached a peak on the 1st postoperative day and decreased to pretreatment values by the 4th day. Creatine phosphokinase and myoglobin also significantly increased on the 1st postoperative day but returned to pretreatment levels by the 4th day. The urinary ratio of N-acetyl-beta-d-glucosaminase to creatinine significantly increased after treatment and was still high on the 4th day. These results suggest that significant hemolysis and myolysis developed owing to shock-wave exposure, and that the kidney was damaged to some extent. Therefore, these side effects must be taken into account in determining the dose and frequency of treatment.

Adult↗
PubMed1986

Suppression of natural killer cell activity by surgical stress in cancer patients and the underlying mechanisms.

The influence of surgical stress on the natural killer (NK) activity of peripheral blood lymphocytes in patients with carcinoma of the lung or gastrointestinal system was studied. The peripheral blood lymphocytes of the patients showed a marked decrease in NK activity against K-562 cells as target cells 1-2 days after surgery. The activity remained lowered for 2 weeks after thoractomy and for 1 week after laparotomy. No appreciable suppression of NK activity was observed with normal human peripheral blood lymphocytes preincubated with postoperative patient sera. Peripheral blood mononuclear cells obtained postoperatively from patients lost NK activity after ultraviolet irradiation, without any detectable loss of viability. Such irradiated mononuclear cells showed inhibition of NK activity after a 24-hour preincubation with peripheral blood lymphocytes from normal subjects. Similar suppressive activity was demonstrable in a fraction of mononuclear cells with adhesiveness to plastic petri dishes, while non-adherent cells had no such activity. When added immediately to the cytotoxicity assay system without the 24-hour preincubation, patient mononuclear cells caused no inhibition of NK activity, whereas adherent cells from normal subjects enhanced NK activity. The findings seems to indicate that, following surgical stress, plastic dish-adherent peripheral blood mononuclear cells become deprived of NK helper activity and exert suppression, thus causing postoperative depression of NK activity.

Gastrointestinal Neoplasms↗
PubMed1986

[A clinical bacteriological efficacy study on a fosfomycin otic solution].

Fosfomycin (FOM) otic solution was administered to 587 patients with suppurative otitis media infections including 190 patients in the dose-establishment test, 126 patients in the open clinical trial and 271 patients in the double blind test. Various bacteria were detected in the 549 cases in which bacteriological investigation was possible. Main bacteria detected from the above cases were S. aureus (261 strains, 47.5%), P. aeruginosa (93 strains, 16.9%), coagulase negative Staphylococci (CNS) (89 strains, 16.2%), Providencia spp. (35 strains, 6.4%) and Proteus spp. (28 strains, 5.1%). Twenty-seven strains of anaerobic bacteria (4.9%) were also detected. The MIC of FOM, and the reference drug, chloramphenicol (CP), fradiomycin (FRM), cefmenoxime (CMX) and cephalexin (CEX), were determined up to a concentration of 800 micrograms/ml with inoculum sizes of 10(6) and 10(8) CFU/ml. About 30% of S. aureus was multi-drug resistant, including methicillin and cephems, but FOM showed excellent antibacterial activity against it. The FOM had superior antibacterial activity against P. aeruginosa to CP, FRM and CMX, and was also active against other bacteria. The antibacterial activity of FOM was inferior to other drugs against CNS, Enterobacter spp., P. putida and P. cepacia. The detection rate of these bacteria, however, was low and since their role as causative organisms is not well defined, the inferior activity of FOM has no effect on the bacteriological evaluation of FOM. Since the concentration in the tympanic cavity about 1 hour after the administration of 3% FOM solution was estimated to be 2,000 to 3,000 micrograms/ml, it could be presumed that bacteria inhibited by 800 micrograms/ml of FOM at an inoculum size of 10(8) CFU/ml would be eradicable. The low ototoxicity of FOM is likely due to its characteristic as an inhibitor of bacterial cell wall synthesis. From these results, 3% FOM otic solution may be considered as a remarkably useful topical preparation for the treatment of suppurative otitis media.

Administration, Topical↗
PubMed1986

[In vitro susceptibilities of BRL 25000 (clavulanic acid-amoxicillin) against causative organisms in the field of obstetrics and gynecology].

The in vitro susceptibilities of various causative organisms recently isolated from patients with genital infections to BRL 25000 (a formulation with 2 parts of amoxicillin and 1 part of potassium clavulanate), amoxicillin (AMPC), cefaclor (CCL), cephalexin (CEX), cefadroxil (CDX) and cefroxadine (CXD) were determined. beta-Lactamase-producing strains were detected by the nitrocefin disc method. Frequencies of isolation of beta-lactamase producing strains of E. coli, K. pneumoniae and B. fragilis were 36%, 96% and 100%, respectively. The activity of BRL 25000 against S. agalactiae and anaerobic GPC (anaerobic Streptococci, Peptostreptococcus spp.) was slightly less than that of AMPC but was 2- to 4-fold higher than CCL and 8- to 16-fold higher than CEX, CDX and CXD. Against E. coli and K. pneumoniae, the activity of BRL 25000 was superior to that of AMPC and approximately equal to CEX, CDX and CXD but 2-fold less than CCL. Against the B. fragilis group, BRL 25000 was much more active than AMPC or any of the cephalosporins tested, clearly demonstrating the beta-lactamase inhibitory properties of the clavulanic acid in BRL 25000. At inocula of 10(6) CFU/ml, MIC values of BRL 25000 were 12.5-50 micrograms/ml against some strains of E. coli, K. pneumoniae and B. fragilis. A mechanism of resistance other than beta-lactamase production is obviously prevalent in these strains. It is speculated that the resistance may be due to a low affinity of the drug to target proteins. Mixed infections of B. fragilis and E. coli or K. pneumoniae are commonly found in the obstetric and gynecological patients. BRL 25000 shows activity against these strains and also against both aerobic and anaerobic GPC. Therefore, BRL 25000 is considered useful for the treatment of genital infections.

Amoxicillin↗
PubMed1986

[Midecamycin acetate-susceptibility of clinical isolates from dental and oral surgical infections].

To investigate the clinical and bacteriological usefulness of orally administered midecamycin acetate (MOM), the susceptibility of clinical isolates to MOM, Mb-12 (the main metabolite of MOM), josamycin (JM), ampicillin (ABPC) and cephalexin (CEX) was determined. The results are summarized as follows. Antibacterial activities of MOM against aerobic Gram-positive cocci, B. catarrhalis, and anaerobic bacteria were inferior to those of JM by 2-fold, but superior to those of CEX. Activities of MOM against S. aureus, Bacteroides spp., Fusobacterium spp., Veillonella spp. were superior to those of ABPC and CEX. Since serum and tissue concentrations of Mb-12 after 200 mg administration in humans have been reported to be 1-2 micrograms/ml, it can be presumed that the causative bacteria would be eradicated by a usual dosage of MOM used in the present study. From these considerations, it is speculated that MOM may be successfully used in the treatment of dental and oral surgical infections.

Ampicillin↗
PubMed1986

[A study of concentration of ampicillin into middle ear effusion after administration of bacampicillin].

We studied the concentration of ampicillin (ABPC) into middle ear effusions after administration of bacampicillin (BAPC). Nine patients with acute purulent otitis media were given orally single doses of the drug at a level of 10 mg/kg, and concentrations of ABPC which is the active antibiotic metabolite of BAPC were determined in middle ear effusions periodically after the administration. Bacteria present in effusions were identified, and their ability to produce beta-lactamase was also determined. ABPC concentrations in middle ear effusions were inversely related to the ability of bacteria detected from the intratympanic cavity to produce beta-lactamase. ABPC concentrations in middle ear effusions from which only beta-lactamase negative organisms were detected were higher by 5.2- and 2.3- fold at 60 and 120 minutes after the administration of BAPC, respectively, than those in effusions from which beta-lactamase positive organisms were detected. ABPC concentrations achieved in middle ear effusions in cases where only beta-lactamase negative organisms were detected exceeded MIC80's of the drug against main causative bacteria of acute purulent otitis media such as Streptococcus pneumoniae, Streptococcus pyogenes, and Haemophilus influenzae. Because only 10% or less of these species produces beta-lactamase, BAPC appears to be one of the highly effective drugs in the treatment of this disease.

Acute Disease↗
PubMed1985

Changes in coagulation and fibrinolysis occurring in dogs during hypothermia.

Changes in fibrinolysis, platelets and coagulation during hypothermia were investigated in anesthetized dogs. Strong activation of plasma fibrinolysis was observed in the hypothermia group. The maximum fibrinolytic activity determined with standard fibrin plates was markedly higher than that of the control sample (mean values: 67 and 15 mm2/0.03 ml plasma, respectively). On the other hand, no fibrinolysis was observed by the plasminogen free plate method. Activation was not observed in the control group or the hypothermia group premedicated with chlorpromazine. The platelet count was decreased from 100% to 14.7% and the collagen induced platelet aggregability from 61% to 2.3% during hypothermia. Recovery from both reductions occurred on rewarming. In the control and premedicated groups, the recalcification time was reduced progressively (from 93.6 to 60.9 sec and from 101.1 to 71.8 sec as mean times, respectively). The tendency towards shortening of the recalcification time was not related to the core temperature.

Animals↗