Biomedical subjects

M Ohtani

Publications and source records attributed to M Ohtani.

At least 19 recordsLinked to original sources

PubMed1992

Purification and characterization of proteinase In, a trypsin-like proteinase, in Escherichia coli.

We previously found a trypsin-like proteinase which momentarily appears immediately before DNA synthesis in the cell cycle of Escherichia coli synchronized by phosphate starvation and which is closely related to the initiation of DNA replication (Kato, M., Irisawa, T., Morimoto, Y. and Muramatu, M., unpublished results). The proteinase was named proteinase In. It was purified approximately 2880-fold with a recovery of 15%. The isolated enzyme appeared homogeneous by gel filtration and electrophoresis. Its molecular mass was estimated by analytical gel filtration and SDS/PAGE as approximately 66 kDa. The isoelectric point of proteinase In is 4.9 and its optimal pH is approximately 9. Although protein In hydrolyzes fluorogenic substrate for trypsin, its hydrolytic activity seems markedly affected by amino-acid sequence lying towards the N-terminal from the P1 (lysine, arginine) residue. The proteinase does not hydrolyze N2-benzoyl-D,L-arginine-4-nitronanilide and fluorogenic substrates for chymotrypsin and elastase. The proteinase activity is inhibited by leupeptin, antipain and 4-nitrophenyl 4-guanidinobenzoate, but the effects of tosyl-L-lysine chloromethane, diisopropylfluorophosphate, benzamidine and pentamidine isethionate on the proteinase activity are weak or not inhibitory. Its activity is strongly affected in the presence of NaCl and KCl, and at a concentration of 1.5 M, these increase the activity 14-fold and 13-fold, respectively, above that without salt. Proteinase In was strongly inhibited by various esters of trans-4-guanidinomethylcyclohexanecarboxylic acid, and their inhibitory effects were roughly correlated with those on growth of E. coli. Proteinase activity was found in the cytoplasmic fraction.

Amino Acid Sequence↗

PubMed1992

[MR angiography enhanced by sodium acetazolamide].

We tried to use sodium acetazolamide to enhance MR angiography (MRA). Sodium acetazolamide, one of carbonic anhydrase inhibitors, has an effect to increase regional cerebral blood flow. We made a direct comparison between pre and post enhanced MRA (both 3D-TOF and 3D-PC techniques). MRA after administration of sodium acetazolamide could depict more details of cortical branches without enhancement of back-ground. So we recommend this simple method to be used widely in any examination of MR angiography.

Acetazolamide↗

PubMed1992

Contraction of guinea pig lung parenchyma by pancreatic type phospholipase A2 via its specific binding site.

Porcine pancreatic group I phospholipase A2 (PLA2-I) induced contraction of guinea pig parenchyma in a concentration-dependent manner. Its EC50 value was similar to the Kd value calculated from the specific binding of 125I-labeled porcine PLA2-I in the membrane fraction of guinea pig lung. Type-specific action of PLA2's and homologous desensitization strongly implicated the involvement of PLA2-I-specific sites in the activation process. Thromboxane A2 was found to be the main product from lung tissue by PLA2-I action and the contractile response by PLA2-I was specifically suppressed by thromboxane A2 receptor antagonists and cyclooxygenase inhibitor, but not by leukotriene receptor antagonist and H1 blocker. These findings indicate that PLA2-I-induced contractile response may depend on the secondarily produced thromboxane A2, thus providing a new aspect of PLA2-I from the pathophysiological standpoint.

Animals↗

PubMed1992

Prospective study of laparoscopic cholecystectomy in two hundred and fifty patients.

Two hundred and fifty consecutive patients (151 women, 99 men, age 49.3 years) with symptomatic gallstones as diagnosed on ultrasonography underwent elective laparoscopic cholecystectomy over a 12-month period. Preoperative intravenous cholangiography (IVC) and endoscopic retrograde cholangiography (ERC) were also performed in 203 and 200 patients, respectively. Laparoscopic cholecystectomy was successfully performed on 248 of the 250 patients (99.2%). Two patients required conversion to open cholecystectomy because of a pin hole injury to the portal vein in one case, and because of technical difficulties with the dissection due to severe adhesions in the other patient. Procedure time in the initial 100 cases decreased from an average of 216 minutes for the first ten cases to 87 minutes for the last 30 cases, including the time required for intraoperative cholangiography (IOC). Bile duct stones were found in 4 cases on IOC which were diagnosed by preoperative ultrasonography, IVC and ERC in 0, 2 and 3 cases respectively. An intraabdominal drain was inserted for two days in all cases. The mean hospital stay was 8.6 days (range 4 to 19 days) with no readmissions. No complications were seen at short-term follow-up one month after discharge. Although there was a significant learning period, the procedure was safe and effective and could be performed with minimal risk. The results show that physicians with experience in both endoscopy and laparoscopy are well qualified to perform laparoscopic cholecystectomy after appropriate training.

Cholangiography↗

PubMed1992

Preliminary experience using laparoscopic transcystic cholangioscopy for treatment of common bile duct stones.

Laparoscopic transcystic cholangioscopy (LTC) in combination with electrohydraulic lithotripsy may be an alternative treatment to ERCP and sphincterotomy in patients with both gallbladder and common bile duct stones undergoing laparoscopic cholecystectomy. Preliminary experience using LTC lithotripsy in 13 cases is reported. In 12 cases the stones were pushed out into the duodenum using the tip of the cholangioscope, in 8 of them stone disintegration via LTC lithotripsy also being required. In the remaining case the cholangioscope could not be inserted into the common bile duct via the cystic duct due to complete cystic duct obstruction. The average hospital stay was 9 days (range 6-16) in patients with LTC/lithotripsy, which did not differ significantly from 8.4 days (range, 4-19) (n = 330) in the group undergoing laparoscopic cholecystectomy alone. The patients usually resumed normal activity the day after discharge. LTC lithotripsy has the advantages over endoscopic sphincterotomy of a shorter treatment and preservation of a normal functioning sphincter of Oddi. Further technical improvements, especially the development of a cholangioscope for this purpose, are urgently required.

Adult↗

PubMed1992

Intracellular free calcium concentrations in single taste receptor cells in the guinea pig.

Single, viable taste receptor cells were isolated from the tongue of the guinea pig by enzymatic digestion and mechanical dissociation. The cells could be classified into flask, spindle and intermediate shapes. The intracellular free calcium ion concentrations [(Ca2+)i] of these cells were determined using the Ca2+ sensitive dye fura-2 and digital imaging microscopy. All types of cells produced an irreversible increase in (Ca2+)i upon addition of Ca2+ ionophore ionomycin (1 microM) and denatonium (10 microM). There was no evidence of any increase in (Ca2+)i in the taste receptor cells in nominally Ca2+ free solution, and when stimulated by denatonium (10 microM). When 3 mM CaCl2 was added, the (Ca2+)i remarkably increased. This would suggest that the (Ca2+)i increase in the presence of denatonium mainly depended on calcium influx from the extracellular space. There was no increase in case of high potassium (50 mM and 150 mM) or saccharose (1 mM and 5 mM) stimulation. The hypothesis that the increase in (Ca2+)i controls biochemical mechanisms related to the bitter taste transduction process is worthy of further study.

Animals↗

PubMed1992

[Promotive effects of intravesical instillation of dimethylsulfoxide on bladder carcinogenesis in mice].

The effect of intravesical instillation of dimethylsulfoxide (DMSO) on bladder carcinogenesis was examined in mice. Experiment 1: Fifty-five female C3H/He mice were administered 0.05% N-butyl-N-(4-hydroxy-butyl) nitrosamine (BBN) in their drinking water for 8 weeks. In week 9 they were divided into two groups consisting of 25 mice each. Then, under nembutal anesthesia the first group was given weekly intravesical inatillations of 0.1 ml DMSO (minimum 99.0%) for 10 weeks. The second group received no treatment except anesthesia. All mice were killed 30 weeks after the begining of the experiment and their urinary bladder resected for histological examination. The incidence of bladder carcinoma was 93.7% (15.16) and 27.7% (6/22) in groups 1 and 2, respectively. These incidences differed significantly between the two groups. Experiment 2: One hundred and twenty female C3H/He mice were divided into two groups. The first group was given 0.05% BBN in their drinking water for 5 weeks and then tap water. The second group was not given BBN. In week 6, the first group was divided again into three groups (1, 2 and 3) consisting of 28, 26, and 27 mice, respectively. The second group was divided into groups 4 and 5 consisting of 21 and 18 mice, respectively. Under nembutar anaesthesia groups 1 and 4 received weekly intravesical instillation of 0.05 ml DMSO (minimum 99.0%) from weeks 6 to 13, Group 2 received weekly intravesical instillation of 0.05 ml distilled water from weeks 6 to 13. Groups 3 and 5 received no treatment except anesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Intravesical↗

PubMed1992

[Antitumor effect of combined use of purified human natural tumor necrosis factor (N-TNF) and cis-diamminedichoroplatinum (II) (cisplatin) on the implanted bladder carcinoma (MBT-2) in mice].

The antitumor effect of tumor necrosis factor (TNF) in combination with Cis-diammine-dichloroplatinum (II) (Cisplatin) upon implanted bladder carcinoma (MBT-2) in mice was analysed together with the toxicity. Mice were implanted into the bladder wall with about 10(4) cells MBT-2 viable cells. TNF was the purified human natural tumor necrosis factor. The antitumor effects were evaluated by the volume of the tumor thus implanted and the drug-toxicity by the body weight of mice and microscopic as well as macroscopic findings of the main organs. As a result, 1) The toxicity of TNF to mice was not enhanced in a dose-dependent fashion when combined with Cisplatin. 2) The antitumor effect by combination of TNF and Cisplatin was significantly increased compared to control group. 3) The effects of TNF was enhanced in a dose-dependent fashion when combined with Cisplatin. 4) The antitumor effects was confirmed by pathological findings. These results suggest that the combined use of n-TNF and Cisplatin is promising as a clinically effective treatment against bladder cancer in human.

Animals↗

PubMed1992

[Comparison of long-term patency rates of transluminal angioplasty and bypass grafting].

We have applied transluminal angioplasty (TAP) and bypass grafting (BG) to the lower-limb ischemia for ten years since 1982. We have treated 176 cases (194 limbs) by TAP and 250 cases (323 limbs) by BG. The TAP treated group was divided into two groups. The first was classified as a stenotic artery group (TAPs) and the other was as an obstructive artery group (TAPs). BG was also divided into two groups, the first belonged to a ringed graft (RPTFE) while the other was a bypass with a saphenous vein (BG sv). The registered patent rates for TAP and TAPs are 61.2%, 75.1% recorded after 5 years and 51.4%, 57.0% after 7 years, respectively. The patent registry rates for BG and RPTFE are evaluated as being 64.2%, 82%, after 5 years and 48.2%, 82% after 7 years, respectively. The results showed that the patent registry rate for BG is significantly better than that of the TAP but the results indicate similarities between TAPs and RPTFE. As a conclusion, we recommend the use of TAP for the stenotic lesion of the artery and RPTFE for obstructive lesion of arteries.

Adolescent↗

PubMed1992

[Laparoscopic cholecystectomy].

Two hundred and fifty consecutive patients with symptomatic gallstones underwent elective laparoscopic cholecystectomy over a ten month period. Out of 250 cases, 2 (0.8%) were converted to open cholecystectomy. One was due to bleeding, and the other being due to severe adhesion. The remaining 248 cases resulted in complete success without any complications or postoperative readmission. In this modality of laparoscopic cholecystectomy, there is an apparent learning experience which can be covered only by adequate training and experience. From an ethical point of view, however, training should not be undertaken at the expense of patients. With less experienced operators, the threshold of indication for laparoscopic cholecystectomy should be set high in order to secure the safety of the patients as well as the successful completion of the procedures.

Adult↗

PubMed1992

Determination of optimal perfusion flow rate for deep hypothermic cardiopulmonary bypass in the adult based on distributions of blood flow and oxygen consumption.

To determine the optimal perfusion flow in deep hypothermic cardiopulmonary bypass at 20 degrees C in human beings, we studied the relationship of perfusion flow to the whole body and to regional oxygen consumption. In adult patients (n = 11, average age 54 years) with valvular or coronary heart disease, the distributions of perfusion flow rate and oxygen consumption were analyzed by dividing into the superior and inferior vena caval areas. Measurements (n = 39) were made at various perfusion flow rates (perfusion flow rate in the superior vena caval area plus that in the inferior vena caval area equals whole-body perfusion flow rate: 0.4 to 2.2 L/min/m2) in a setting of average hemoglobin levels of 8.1 gm/dl. Between whole-body perfusion flow rate and oxygen consumption (total oxygen consumption equals superior plus inferior vena caval oxygen consumption), there was a hyperbolic correlation (r = 0.73; p less than 0.001; asymptote = 29.0 ml/min/m2). A positive linear correlation was found between whole-body perfusion flow rate and inferior vena caval oxygen consumption (r = 0.75; p less than 0.001), whereas no significant relation was seen between whole-body perfusion flow rate and superior vena caval oxygen consumption. For distributional changes in inferior vena caval perfusion flow rate/whole body perfusion flow rate and inferior vena caval oxygen consumption/whole body oxygen consumption, the broken-line regression analysis showed respective critical points where both parameters started to drop when whole-body perfusion flow rate was gradually reduced: 1.2 L/min/m2 for inferior vena caval perfusion flow rate/whole-body perfusion flow rate and 0.8 L/min/m2 for inferior vena caval oxygen consumption/whole-body oxygen consumption. The results indicate that (1) the oxygen consumption to the superior vena caval area was maintained independent of the perfusion in a relatively wide range in contrast to that for the inferior vena caval area and (2) when the redistribution of oxygen consumption is considered as undesirable under low-flow perfusion, the optimal perfusion flow for 20 degrees C deep hypothermic cardiopulmonary bypass appeared to be 0.8 L/min/m2.

Adult↗

PubMed1991

Urophonographic studies of benign prostatic hypertrophy.

The sonic detection and recording systems of urethral sounds generated during micturition were developed. This procedure was tentatively postulated as "urophonography" and its recording diagram as a "urophonogram". Classification of urophonograms was done on the basis of analyzing normal healthy male volunteers and patients with benign prostatic hyperplasia. Four types of urophonograms were demonstrated according to the shape and characteristics. Types 1, 2, 3 and 4 were characterized by a diamond shape, irregular occurrences of sound spikes, the mixture of Types 1 and 2 and no remarkable sound spikes respectively. Types 1, 2, and 3 were found in BPH, while Type 4 was demonstrated in normal healthy male volunteers. After prostatectomy a high percentage of Type 4 was demonstrated. The frequency (Hz) of these sounds was around 650. Diamond shape sound showed higher value of power gain (dB) than irregular type sound. The wave length was around 0.50 (m). Comparison of urophonographic studies with conventional uroflowmetric investigation was undertaken. Urophonography was useful for investigations of dysfunctional voiding and lower urinary tract obstruction.

Aged↗

PubMed1991

FTIR spectral study of intramolecular hydrogen bonding in thromboxane A2 receptor antagonist S-145 and related compounds. 3. Conformation and activity of S-145 analogues.

S-145, (+/-)-(5Z)-7-[3-endo-[(phenylsulfonyl)amino]bicyclo[2.2.1] heptenoic acid, its chain analogues HO2C(CH2)nNHSO2Ph (n = 3-8, 10, and 11) 1-8, and (5Z)-9-(phenylsulfonyl) aminonon-5-enoic acid (9) were synthesized in order to elucidate the dependence of the conformation in solution and of the pharmacological activity on the side-chain length. Their FTIR spectra were measured in dilute CCl4 solution. For these compounds, intramolecular hydrogen bonds similar to those observed for S-145 were found between the carboxyl and sulfonamido groups. A linear relationship was also found between the percentage (rho) of the intramolecular hydrogen-bonded molecules and the n value. Compounds 1-9 were examined in vitro for inhibitory concentrations (IC50) against U-46619- and collagen-induced aggregations for rabbit and rat washed platelets (WP), respectively, and U-46619-induced contraction for rat aorta. Three kinds of TXA2 receptor antagonistic potencies [log(1/IC50)] showed parabolic correlations with the n value, though the rho value was in direct proportion to the n value. The log (1/IC50) values for 6 (n = 8), which forms a 12-membered ring similar to the one observed for S-145, were found to be maximal values in 1-8 and were comparable to those for BM-13177. In compounds 9 (rho = 83%) and S-145 (rho = 89%), the IC50 values of 41 and 2.9 nM for rat WP were 10 and 141 times lower than that of 6 (rho = 52%), respectively. In these compounds, which form the 12-membered ring, the inhibitory potencies increase as the rho value increases.

Animals↗

PubMed1991

A new approach to in situ left ventricular volume clamping in dogs.

Major contributing factors modulating left ventricular (LV) diastolic behavior are active relaxation of myocardium and volume change during filling, the interaction of which complicates analysis of diastolic pressure-volume relationship, especially in early diastole. To separate the effect of active relaxation and filling, a method was introduced [E. L. Yellin, M. Hori, C. Yoran, E. H. Sonnenblick, S. Gabbay, R. W. M. Frater, Am. J. Physiol. 250 (Heart Circ. Physiol. 19): H620-H629, 1986] to interrupt mitral inflow and keep LV volume constant throughout diastole. Their preparation requires replacing the mitral valve with an artificial valve using cardiopulmonary bypass, which might cause significant change in cardiac performance or produce detrimental systemic effects. We developed a new volume-clamping method that preserves the native mitral valve and apparatus intact and avoids cardiopulmonary bypass. A modified Bjork-Shiley prosthetic valve (20 mm orifice diam) in a special mounting ring was placed above the native mitral valve through the left atrium and secured from outside the heart. This prosthetic valve was controlled by a cable connected to solenoids outside the dog, triggered by the electrocardiogram or other physiological signal. We compared our method (n = 7) with that of Yellin et al. (n = 2) in nine random source dogs. In our method, no end-diastolic pressure gradient or regurgitant pressure wave was observed, and the prosthetic valve did not disturb movement of the native mitral valve. When the prosthetic valve was forced to a closed position at end systole, LV volume, measured with a conductance catheter, was maintained at or near end-systolic volume throughout diastole.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Isolation of and calcium mobilization in vestibular hair cells of the guinea pig.

Vestibular hair cells were isolated from the macula utriculi, macula sacculi and crista ampullaris of the guinea pig, using enzymatic and mechanical techniques. The cells could be classified into two types: flask-shaped ones with a neck and rod- or round-shaped ones without a neck. The flask-shaped cells were thought to be type I cells, the rod-shaped cells type II cells, while the round-shaped cells could have been type I or type II cells. The intracellular free calcium ion concentrations [( Ca2+]i) of these cells were determined using the Ca2(+)-sensitive dye Fura-2 and digital imaging miroscopy. In the resting state, [Ca2+]i in the nucleus and cuticular plate was variable in both types of cells. The 150 mM KCl stimulation, which might induce a depolarization, resulted in a temporary increase in [Ca2+]i in both types of cells. In the presence of 1 micron ionomycin, there was an irreversible increase in [Ca2+]i in both types of cells. These observations aid in elucidating vestibular function.

Animals↗

PubMed1991

Evaluation of the invasive potential of superficial bladder cancer by adenosine triphosphate measurement.

In order to predict the malignant potential of superficial bladder cancer, in 121 patients with this malignancy adenine nucleotide levels (adenosine triphosphate, adenosine diphosphate, and adenosine monophosphate) and energy charge in bladder cancer cells were determined. The nucleotides were analyzed according to the method of Bücher, and the energy charge was calculated by applying the formula of Atkinson. It was clearly pointed out that superficial bladder tumors, which became invasive and/or metastatic, had higher levels of adenylate compounds than those which became not. Our results show that a high correlation exists between adenine nucleotide content and tumor progression.

Adenosine Diphosphate↗

PubMed1991

Synthesis of metabolites of S-1452, an orally active thromboxane A2 receptor antagonist.

The synthesis of 16 metabolites of S-1452, an orally active thromboxane A2 (TXA2) receptor antagonist, is described. Regioselective hydroxylation at C-5 or C-6 of the bicyclo[2.2.1]heptane skeleton of the optically active intermediate 16 was attempted by using 9-borabicyclo[3.3.1]nonane followed by H2O2 or m-chloroperbenzoic acid (m-CPBA) and then LiA1H4, to obtain the hydroxylated product 17a or 17b, respectively. Modification of the C-2 substituent of 17a and 17b afforded eight metabolites of S-1452. Eight non-hydroxylated metabolites were synthesized by using a similar reaction sequence.

Animals↗

PubMed1991

Isolation of and calcium kinetics in cochlear inner hair cells of the guinea pig.

Single inner hair cells of the guinea pig cochlea were isolated using enzymatic and mechanical techniques. The intracellular free calcium ion concentrations [( Ca2+]i) of the isolated inner hair cells were determined using the Ca2+ sensitive dye fura-2 and digital imaging microscopy. In the presence of 1 micron ionomycin, a Ca2+ ionophore, there was an irreversible increase in [Ca2+]i. The 150 mM KCl stimulation, which induces a depolarization, resulted in a temporary increase in [Ca2+]i. This increase in [Ca2+]i was not observed under conditions of depolarization, in Ca(2+)-free medium. These observations are interpreted to mean that the [Ca2+]i during membrane depolarization mainly originates from an influx of extracellular Ca2+ into the cytoplasm.

Animals↗