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Biomedical subjects

J Mukai

Publications and source records attributed to J Mukai.

At least 37 records · Page 2Linked to original sources
PubMed1993

Long-term results of catheter ablation for idiopathic ventricular tachycardia originated from the right ventricular outflow.

We performed catheter ablation in 10 consecutive patients with idiopathic monomorphic right ventricular tachycardia and studied the long-term outcome. All ventricular tachycardias had a left bundle branch block configuration with an inferior axis, and originated from right ventricular outflow. Antiarrhythmic drugs (3-6 drugs) had been ineffective in controlling ventricular tachycardia. The 2 patients who underwent direct-current ablation (2 shocks of 150 J) had no recurrence of ventricular tachycardia and did not require antiarrhythmic drugs during a follow-up of 56 and 51 months, respectively. Of the 8 patients who underwent radiofrequency ablation (30-40 watt, 20-40 sec, 2-15 application, using Inter Nova RA 50, 13.56 MHz), 1 patient had no recurrence of ventricular tachycardias and did not require antiarrhythmic drugs, 4 patients had no recurrence of ventricular tachycardias but did require anti-arrhythmic drugs, and 3 patients experienced recurrence of non-sustained ventricular tachycardia despite the use of antiarrhythmic drugs during a follow-up of 15-40 months. There were no complications except for cardiac perforation which occurred immediately after direct-current ablation in 1 patient. In conclusion, long-term success in preventing ventricular tachycardia was achievable with direct-current ablation, but this success was associated with serious risks, such as cardiac perforation. Radiofrequency ablation was safer than direct-current ablation, but had a lower long-term success rate.

Adult↗
PubMed1993

Enzymology and gene technology of Streptomyces nucleotide 3'-pyrophosphokinase-2',3'-cyclic monophosphokinase (PPKase).

Streptomyces extracellular nucleotide 3'-pyrophosphokinase-2',3'-cyclic monophosphokinase transfers 5'-beta,gamma-pyrophosphate group from ATP, some ATP derivatives and dATP to a variety of nucleot(s)ides at the 3'-OH site and synthesizes the respective 3'-pyrophosphoryl nucleotides. The enzyme also utilizes A-5'-pn (n = 3-5)-5'-N, transferring their adenosine 5'-pyrophosphoryl group and concomitantly eliminating the AMP moiety therefrom, leading to the synthesis of 2',3'-cyclic monophosphoryl nucleotides. The enzyme gene and its neighbouring up- and downstream sequences were analyzed. Streptomyces and enteric bacteria E. coli and Klebsiella pneumoniae transformants were constructed by incorporation of the pyrophosphokinase gene-recombined expression plasmids. Various effects of the treatments--intracellular synthesis of 3'-pyrophosphoryl nucleotides, retarded cellular growth, stimulated N2 fixation by K. pneumoniae and so on--were seen.

Adenine Nucleotides↗
PubMed1993

[The effects of pharmacological autonomic blockade on the conduction system in patients with and without sinus node dysfunction].

Electrophysiological studies were performed in 26 patients with sick sinus syndrome (SSS) and 12 controls before and after pharmacologic autonomic blockade (PAB) with propranolol (0.15 mg/kg) and atropine (0.04 mg/kg). Sinus cycle length (SCL) shortened significantly after PAB in both groups. PA and HV intervals did not change after PAB. AH interval shortened and Wenckebach period increased after PAB in SSS group. Maximum corrected sinus node recovery time shortened in the control group but did not change in the SSS group after PAB. Calculated sinoatrial conduction time shortened after PAB in both groups. Refractory periods of the atrioventricular (AV) node and the ventricle shortened significantly, but those of the atrium did not change after PAB. Linear relations existed between the change of SCL and the change of AH interval and of the Wenckebach period. These results suggested that the autonomic nervous system had the same effects on the sinus and the AV nodes in patients with SSS, and that parasympathetic tone was predominant on the sinus node, the perinodal tissue and the AV node under resting conditions.

Atropine↗
PubMed1992

Granulocyte-colony-stimulating factor enhances the circulating hematopoietic progenitors in lung cancer patients treated with cisplatin-containing regimens.

A phase II study examining the effects of human recombinant granulocyte-colony-stimulating factor (G-CSF) on the growth of colony-forming unit-granulocyte macrophage (CFU-GM) in the bone marrow and in the peripheral blood was performed in lung cancer patients treated with cisplatin-containing regimens. Treatment with G-CSF following chemotherapy significantly increased the absolute granulocyte count. No significant effect of G-CSF on either the platelet or the red blood cell count was observed. Treatment with G-CSF did not affect the CFU-GM levels in the bone marrow, but did have a significant effect on peripheral blood CFU-GM levels 14 days after initiation of chemotherapy (P less than 0.05). Four patients demonstrated a rebound increase in the level of peripheral blood CFU-GM during the first course of chemotherapy without G-CSF. In contrast, eight patients displayed increase in peripheral blood CFU-GM levels during the second course of chemotherapy with G-CSF treatment. These findings demonstrate that G-CSF is a potent stimulator of granulocyte proliferation as well as a potent agent for promoting transport of hematopoietic progenitors from the bone marrow into the peripheral blood.

Aged↗
PubMed1992

Effect of chemotherapy on colony-forming unit-granulocyte macrophage from bone marrow and peripheral blood in patients with lung cancer.

The effects of chemotherapy on the growth of colony forming unit-granulocyte macrophage (CFU-GM) from the bone marrow (BM) and peripheral blood (PB) of 8 patients with lung cancer were studied by using recombinant interleukin-3, granulocyte macrophage-colony stimulating factor, and granulocyte-colony stimulating factor. After chemotherapy, the kinetics of CFU-GM depend on the type of chemotherapeutic regimens used: a rebound overshoot of CFU-GM in the PB was seen in the 4 patients treated with cisplatin plus etoposide (PVP) but not in the 4 patients treated with cisplatin plus mitomycin plus vindesine (CMV). In the BM, the recovery of CFU-GM was more retarded in patients treated with CMV relative to that seen in patients treated with PVP. The results obtained in simultaneous cultures revealed the differences between CMV and PVP in the kinetics of chemotherapy-induced myelosuppression. Determination of the optimal timing of in vivo use of hematopoietic growth factors after cytoreductive chemotherapy requires careful experimental design.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

[Molecular cardiopharmacology of selective inhibitors of cyclic nucleotide phosphodiesterase isozymes].

The existence of multiple isozymes of cyclic nucleotide phosphodiesterase (PDE) in many tissues including the heart has been demonstrated. Five isozyme families, each composed of several subtypes and having different tissue and subcellular distributions, have been characterized. Selective inhibitors of PDE III (cGMP-inhibited PDE) elevates the cAMP level which mediates positive inotropic actions with compartmentation of cAMP related to cardiac cell particulate structures. Both cardiac cytosolic and particulate PDE III were potently and selectively inhibited by the new cardiotonic agents competitively with respect to cAMP, except for vesnarinone. There might be at least two subtypes of PDE III, and vesnarinone may be a selective subtype inhibitor of PDE III in human heart. It was also reported that vesnarinone was beneficial in treating patients with congestive heart failure. Moreover, selective inhibitors of PDE III with ancillary properties such as calcium sensitization may prove to be more useful drugs for the treatment of heart failure.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1992

Streptomyces ATP nucleotide 3'-pyrophosphokinase and its gene.

Streptomyces ATP nucleotide 3'-pyrophosphokinase is an extracellular, ribosome-independent, and stringent factor-mimic ppGpp synthetase with an unusually broad acceptor spectrum. The gene-containing DNA fragments cloned from chromosomal DNA of a producer S. morookaensis into pIJ699 and pUC plasmids were found to express the active enzyme in the transformed S. lividans TK24 and enteric E. coli JM109 and nitrogen-fixing Klebsiella pneumoniae M5a1 and 5022, respectively. Base sequence of the structural gene and the deduced amino acid sequence exhibited little homology to those of E. coli stringent factor and related proteins. Growth retardation was seen in some transformants.

Base Sequence↗
PubMed1991

Pharmacokinetics of bronchial artery infusion of mitomycin in patients with non-small cell lung cancer.

The pharmacokinetics of bronchial artery infusion of 20 mg (11.4-14.0 mg/m2) mitomycin was studied in 14 patients with non-small cell lung cancer (NSCLC). The mean elimination half-life was 34.3 min (range 6-72), and the area under the plasma concentration-time curve (AUC) was 166 ng h/ml (39-312). The mean maximum plasma drug concentration (Cmax) was 178 ng/ml (12-540) and back-extrapolated plasma drug concentration was 308 ng/ml (17-1423). The mean volume of distribution in the one-compartment model was 0.183 l/kg (0.010-0.887) and the rate constant for unchanged drug appearing in the urine was 1.91/min (0.57-7.27). There was considerable variation among individuals with respect to the pharmacokinetics of mitomycin, and the mean Cmax and AUC were lower than those reported after intravenous administration.

Bronchial Arteries↗
PubMed1991

[An elderly case of small cell lung cancer showing a good partial response by chronic daily administration of oral etoposide].

An 86-year-old man was admitted to our hospital with complaints of dyspnea and productive cough, and diagnosed as small cell lung cancer with sputum cytology. We concluded that he was unsuitable for standard aggressive intravenous chemotherapy because of an old age, a poor performance status and cardiac complication. He was treated with oral etoposide (100 mg/day x 16.5 days), and showed a good partial response and improvement of clinical symptoms. Toxicities were leukopenia, alopecia, and anorexia. Daily oral administration of etoposide is considered to be effective and useful for elderly patient with small cell lung cancer.

Administration, Oral↗
PubMed1990

Efficacy and safety of catheter electrical ablation for ventricular tachycardia--experimental and clinical studies.

We studied the factors determining the extent of myocardial damage induced by catheter electrical ablation in 23 mongrel dogs and evaluated the efficacy and safety of catheter electrical ablation in 6 patients with medically refractory ventricular tachycardias (VT). Electrical shocks were delivered on the epicardium (EPI) and endocardium (END) of the ventricular wall of open-chest anesthetized dogs through a 6F USCI electrode catheter. Effect of the extent of electrode contact pressure was examined by the presence or absence of monophasic action potential using the contact electrode technique. The former was defined as the hard touch condition and the latter was defined as the soft touch condition. The myocardial lesion induced by EPI fulguration was larger than that by END fulguration (EPI-100 J soft touch: 10.2 +/- 2.9 mm in diameter, 6.6 +/- 1.6 mm in depth vs END-100 J soft touch: 7.7 +/- 1.7 mm in diameter, 5.0 +/- 1.2 mm in depth; p less than 0.05, p less than 0.05). The lesion diameter and lesion depth were enlarged by increasing the amount of delivered energy. The lesion depth by the hard touch condition was significantly greater than by the soft touch condition. The transmural perforation was observed in all EPI fulguration in the hard touch condition of the right ventricular wall. In the clinical study, one to three shocks (mean 1.8 +/- 0.7) of 60 to 200 J (mean 151 +/- 48 J) were delivered per session in 6 patients with medically refractory VT.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Nucleotide 2',3'-cyclic monophosphokinase from actinomycetes.

Streptomyces nucleotide 3'-pyrophosphokinase does not only transfer the 5'-beta, gamma-pyrophosphoryl group of ATP, ATP 3'-pyrophosphate or dATP to a variety of nucleotides at the 3'-OH site, but also adds 2',3'-cyclic terminal monophosphate to some suitable nucleotides with the use of diadenosine 5',5'-polyphosphates (n = 3-5). Examples are pA greater than p, ppA greater than p, pG greater than p, CpG greater than p, etc.

Adenosine Triphosphate↗
PubMed1990

[Familial complete atrioventricular block of adult onset].

A family of complete atrioventricular block (FCAVB) of adult onset was reported. A 36-year-old-female had 1 degree AH block, atrial and ventricular premature beats and mild sinus node dysfunction. Her father had complete AV block and died of it. A 57-year-old uncle and a 52 years-old uncle had bradycardia from 44, 5 years of age and 51 years of age, respectively, and their ECG showed complete AV block with narrow QRS waves. They were implanted with permanent pacemakers. Her grandmother died a sudden death of Adams-Stokes attack. Acquired heart diseases were not seen in any of the family Thus, this family was thought a FCAVB of adult onset.

Adult↗
PubMed1990

[A case of cardiac tamponade showing respiratory variation in inflow and outflow velocities in both ventricles and venous return].

A case of a 62-year-old man with a large pericardial effusion is presented. He developed clinical signs of cardiac tamponade. Two-dimensional echocardiography revealed collapse of the right ventricle in early diastole and inversion of the free wall of both atria in systole. Pulsed Doppler echocardiography demonstrated an abnormally increased respiratory variation in transvalvular blood flow velocities. Expiration caused an increase in the flow velocities across the mitral and aortic valves, and a decrease in the flow velocity across the tricuspid valve. The exaggerated respiratory variations in transvalvular flow velocities suggest that Doppler evaluation may be a valuable adjunct in the diagnosis of cardiac tamponade.

Blood Flow Velocity↗
PubMed1989

Streptomyces nucleotide 3'-pyrophosphokinase are insensitive to stringent control.

The synthesis of GTP- and ATP-3'-pyrophosphate by Streptomyces morookaensis nucleotide 3'-pyrophosphokinase was little affected by the presence of a ribosome-deacylated tRNA-poly A, G, U mixture in vitro. The Streptomyces pyrophosphokinases thus do not appear, unlike bacterial stringent factors, to play a significant role in the cellular stringent control.

Adenosine Triphosphate↗
PubMed1989

[Pilot combination phase II study of mitomycin C plus cisplatin for non-small cell lung cancer].

Fifteen patients (six patients with adenocarcinoma, seven patients with squamous cell carcinoma, and two patients with large cell carcinoma) with advanced non-small cell lung cancer (NSCLC) were evaluable for mitomycin C (MMC; 8 mg/m2 day 1, 8, every 3-4 weeks) plus cisplatin (CDDP; 80 mg/m2 day 1, every 3-4 weeks). Ten patients had had prior chemotherapy. Among 15 evaluable patients, no patient achieved complete response, and two patients showed partial response. The response rate of MMC plus CDDP against NSCLC was 13.3%. Toxic effects included anorexia (80%), nausea and vomiting (67%), leukopenia (53%), anemia (47%), nephrotoxicity (47%), thrombopenia (27%), liver injury (27%), and fever (7%). These toxic effects were reversible and manageable. The combination of MMC and CDDP appears to be valuable regimen against advanced NSCLC.

Aged↗