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Biomedical subjects

A Yoshimoto

Publications and source records attributed to A Yoshimoto.

At least 37 records · Page 2Linked to original sources
PubMed1999

Finger bougie method compared with pyloroplasty in the gastric replacement of the esophagus.

To elucidate the necessity of pyloroplasty for the gastric tube through the posterior mediastinum in esophageal surgery, gastric emptying and duodenogastric reflux (DGR) were evaluated in 16 cases undergoing an anterior pylorectomy (group P) and in 16 cases treated by the finger bougie method (group F). First, the obstruction and reflux symptoms were examined based on a patient questionnaire using a brief scoring system. The median value of the symptom score showed the patients in P to have more symptoms than those in F; however, the difference was not significant (8.0 vs 6.0). Secondly, the swallowed Tc O4- (85MBq) was counted using a gamma camera at three sites on the sternal bone in the upright position based on a gastric transit scintigram. Both the descending time of the RI peak and the clearance rates were similar between the two groups. Thirdly, intragastric 24-h pH monitoring was carried out. Antimony pH sensors were anchored 5 and 15cm below the esophagogastrostomy. We could not find any difference between the two groups in both the %time pH > 4 and %time pH > 7. These findings thus revealed no big difference between groups P and F. The finger bougie method to drain the vagotomized posterior mediastinal stomach was found to achieve results similar to conventional pyloroplasty, while it was also simpler and safer.

Adult↗
PubMed1999

Functional expression of the ascofuranone-sensitive Trypanosoma brucei brucei alternative oxidase in the cytoplasmic membrane of Escherichia coli.

Trypanosome alternative oxidase (TAO) is the terminal oxidase of the respiratory chain of long slender bloodstream forms (LS forms) of African trypanosoma, which causes sleeping sickness in human and nagana in cattle. TAO is a cytochrome-independent, cyanide-insensitive quinol oxidase and these properties are quite different from those of the bacterial quinol oxidase which belongs to the heme-copper terminal oxidase superfamily. Only little information concerning the molecular structure and enzymatic features of TAO have been available, whereas the bacterial enzyme has been well characterized. In this study, a cDNA encoding TAO from Trypanosoma brucei brucei was cloned into the expression vector pET15b (pTAO) and recombinant TAO was expressed in Escherichia coli. The growth of the transformant carrying pTAO was cyanide-resistant. A peptide with a molecular mass of 37 kDa was found in the cytoplasmic membrane of E. coli, and was recognized by antibodies against plant-type alternative oxidases from Sauromatum guttatum and Hansenula anomala. Both the ubiquinol oxidase and succinate oxidase activities found in the membrane of the transformant were insensitive to cyanide, while those of the control strain, which contained vector alone, were inhibited. This cyanide-insensitive growth of the E. coli carrying pTAO was inhibited by the addition of ascofuranone, a potent and specific inhibitor of TAO ubiquinol oxidase. The ubiquinol oxidase activity of the membrane from the transformant was sensitive to ascofuranone. These results clearly show the functional expression of TAO in E. coli and indicate that ubiquinol-8 in the E. coli membrane is able to serve as an electron donor to the recombinant enzyme and confer cyanide-resistant and ascofuranone-sensitive growth to E. coli. This system will facilitate the biochemical characterization of the novel terminal oxidase, TAO, and the understanding on the mechanism of the trypanocidal effect of ascofuranone.

Animals↗
PubMed1999

Structure and regulatory expression of a single copy alternative oxidase gene from the yeast Pichia anomala.

To investigate the regulatory mechanism of alternative oxidase gene expression, genomic DNA was cloned from the yeast Pichia anomala. Genomic Southern blot analysis suggested that a single copy nuclear gene encoded an alternative oxidase in the yeast. The nucleotide sequence showed an uninterrupted coding region for the alternative oxidase protein. In the upstream region from the transcription initiation site found by primer extension analysis, CCAAT, TATAA, and UAS2-like elements were detected. The UAS2 is the element involved in transcriptional regulation by carbon source and the target site for the factor, HAP2/3/4/5 protein complex, in Saccharomyces cerevisiae. By a gel mobility shift assay, a specific retardation band was detected when a protein extract from cells grown on an inducing carbon source was incubated with a UAS2-containing probe. These results suggest that carbon source regulation of alternative oxidase gene expression is mediated by the UAS2-like element and a HAP-like factor in P. anomala.

Amino Acid Sequence↗
PubMed1999

Promotion of antibiotic production by high ethanol, high NaCl concentration, or heat shock in Pseudomonas fluorescens S272.

A stress imposed by a continuous feed of high ethanol, high NaCl concentration, or a high temperature shock increased antibiotic production by several times in Pseudomonas fluorescens S272. A tentative bioassay showed that the stress caused about 40-fold elevation in the autoinducer activity. Addition of synthetic autoinducers, N-(3-oxododecanoyl)-L-homoserine lactone or N-(3-oxohexanoyl)-L-homoserine lactone at a concentration of more than 100 micrograms/l to a non-stressed culture also increased the antibiotic production by several times. These results suggested that the antibiotic production in P. fluorescens S272 was regulated by N-acyl-homoserine lactone and the promotive effect by stress occurred through any function that increased the autoinducer production.

4-Butyrolactone↗
PubMed1999

[Anatomy of intrahepatic portal branches visualized by three-dimensional imaging analysis of CT arterial portography].

The purpose of this study was to clarify variations in intrahepatic portal branches by means of CT imaging procedures. The subjects were 73 patients, 59 men and 14 women, who ranged in age from 41 to 76 years, with a mean of 63 years. The procedures were as follows. The entire liver was scanned using helical CT during the portal and hepatic venous phases, and 3D images of the portal vein were reconstructed with the volume-rendering technique and the region-growing method. The CT unit was a HITACHI W2000, and the imaging analyzer a Sun Ultra 1. We found that the branching patterns of both the anterior (P5 and P8) and posterior segmental branches (P6 and P7) of the right lobe of the liver could be classified into four types. The caudate branch (P1) and left lateral segmental branches (P2 and P3) were classified into three types, and the interior segmental branch of the left lobe (P4) was classified into two types. The frequency of each pattern was also revealed. These branching types and their frequencies were generally the same as those described in previous reports. Thus, the portal anatomy visualized by these methods indicates that they could be very useful for preoperative examinations or IVR.

Adult↗
PubMed1998

[Arterial infusion of SMANCS-Lipiodol for advanced hepatocellular carcinoma].

Twenty-four patients were treated with arterial infusion of SMANCS dissolved in Lipiodol. Twenty of these patients had HCC with the main trunks of portal vein occluded by tumor, and four patients had severe cirrhosis and multiple HCC. The actual dose of SMANCS administered each patient ranged from 4 to 6 mg. Side effects occurred in 50%. Severe side effects such as shock and shivering-chilliness were observed in 18%. The differences between the values of hepatic functional serum indexes obtained before and after treatment with SMANCS were small and transient. With regard to the therapeutic response of the arterial infusion of SMANCS, the mean survival time was approximately 2.8 months. It was suggested that the more effective administration of SMANCS was combination of the arterial infusion of SMANCS-Lipiodol with TAE at the level of the right hepatic artery of left hepatic artery for multiple HCC.

Antineoplastic Agents↗
PubMed1997

Enhancing effect of thoraco-laparotomy on liver metastasis and the role played by active oxygens in its mechanism.

The enhancing effect on liver metastasis produced by the excessive surgical stress of thoraco-laparotomy (TL), and its regulation with a radical scavenger, were studied in 10-week-old Donryu rats. The rats were divided into three groups: those given thoraco-laparotomy for 1 h (the TL group); those given laparotomy alone for 1 h (the L group); those given a short laparotomy (the C group). The effects of treatment with 5 mg/kg of EPC-K1 was assessed in the TL group. A rat hepatocellular carcinoma cell line AH 60C (5 x 10(5) cells) was administered into the portal vein under general anesthesia. The number of metastatic liver nodules was counted 3 weeks later, and the lipid peroxide (LPO) levels of the liver and serum were measured by the TBA method on postoperative days (PODs) 1, 2, and 3. The number of metastatic liver nodules was 40.6 +/- 29.7, 15.0 +/- 15.8, and 13.7 +/- 9.4 in the TL, L, and C groups, respectively. When EPC-K1 was administered to the TL group, the LPO level on POD 1 decreased from 49.8 +/- 25.8 to 18.9 +/- 7.9 nM/g, and the number of metastatic liver nodules decreased from 27.2 +/- 30.0 to 8.9 +/- 12.7 in parallel. The findings of this study suggested that the excessive surgical stress produced by thoraco-laparotomy enhanced liver metastasis in parallel with an increase in LPO levels; however, the radical scavenger EPC-K1 could aid in reversing this effect.

Animals↗
PubMed1997

An antibiotic, ascofuranone, specifically inhibits respiration and in vitro growth of long slender bloodstream forms of Trypanosoma brucei brucei.

Ascofuranone, a prenylphenol antibiotic isolated from a phytopathogenic fungus, Ascochyta visiae, strongly inhibited both glucose-dependent cellular respiration and glycerol-3-phosphate-dependent mitochondrial O2 consumption of long slender bloodstream forms of Trypanosoma brucei brucei. This inhibition was suggested to be due to inhibition of the mitochondrial electron-transport system, composed of glycerol-3-phosphate dehydrogenase (EC 1.1.99.5) and plant-like alternative oxidase. Ascofuranone noncompetitively inhibited the reduced coenzyme Q1-dependent O2 uptake of the mitochondria with respect to ubiquinol (Ki = 2.38 nM). Therefore, the susceptible site is deduced to be the ubiquinone redox machinery which links the two enzyme activities. Further, ascofuranone in combination with glycerol completely blocked energy production, and potently inhibited the in vitro growth of the parasite. Our findings suggest that ascofuranone might be a promising candidate for the chemotherapeutic agents of African trypanosomiasis.

Animals↗
PubMed1997

Effects of nucleotides on cyanide-resistant respiratory activity in mitochondria isolated from antimycin A-treated yeast Hansenula anomala.

Mitochondria were isolated from Hansenula anomala induced for cyanide-resistant respiration by antimycin A-treatment. Cyanide-resistant respiratory activity in isolated mitochondria was stimulated by AMP, ADP, dAMP, and GMP, but not by ATP, adenosine, cAMP, 2'(3')-AMP, CMP, and UMP. Effects of nucleotides were also observed on cyanide-resistant and salicylhydroxamate-sensitive decylubiquinol oxidase activity. Carbonylcyanide m-chlorophenylhydrazone, oligomycin, and carboxyatractyloside did not affect activation of decylubiquinol oxidase activity by AMP. It is suggested that purine nucleoside 5'-monophosphate or diphosphate stimulates alternative oxidase activity from the outer surface of the mitochondrial inner membrane with a mechanism different from respiratory control. Alternative oxidase activity might be controlled by adenine nucleotides posttranscriptionally in fungi.

Adenine Nucleotides↗
PubMed1997

Long-term follow-up study on drop-out TMD patients with self-administered questionnaires.

Although patient attrition might be a serious threat to the validity of treatment-outcome studies on temporomandibular disorders (TMD), studies on TMD patient attrition are scarce. Of the 1405 consecutive TMD patients examined in a recent 10-year period, 367 (26.1%) drop-out patients or patients identified with a control group were sampled. A mailed questionnaire failed to reach 41 patients, and 203 (62.3%) were returned. The questionnaire elicited information on reasons for dropping out, changes in symptoms, treatment received in other clinics after dropping out, present treatment needs, and current signs and symptoms. Dropouts were divided into two groups: (1) those who failed to show up for their first scheduled appointment after the clinical examination; (2) those who failed to complete treatment. A group of patients who were judged by the examiner not to need treatment were included as a control group. The main reasons for dropping out were environmental obstacles, perceived improvement of the disease, and dissatisfaction with services. Only 21.7% considered themselves to be in need of treatment, and only 10.3% had visited other clinics after dropping out. Only 8.9% complained of the continued aggravation of symptoms, whereas 57.6% reported improvement. In addition, pain, dysfunction, and daily activity limitation tended to improve with time, although temporomandibular joint noise tended to persist. These results suggest that TMD signs and symptoms tend to decrease in patients after dropping out, and that the natural fluctuation of TMD signs and symptoms should be taken into consideration when treating TMD.

Adolescent↗
PubMed1996

An antibiotic, ascofuranone, specifically inhibits respiration and in vitro growth of long slender bloodstream forms of Trypanosoma brucei brucei.

Ascofuranone, a prenylphenol antibiotic isolated from a phytopathogenic fungus, Ascochyta visiae, strongly inhibited both glucose-dependent cellular respiration and glycerol-3-phosphate-dependent mitochondrial O2 consumption of long slender bloodstream forms of Trypanosoma brucei brucei. This inhibition was suggested to be due to inhibition of the mitochondriai electron-transport system, composed of glycerol-3-phosphate dehydrogenase (EC 1.1.99.5) and plant-like alternative oxidase. Ascofuranone noncompetitively inhibited the reduced coenzyme Q1-dependent O2 uptake of the mitochondria with respect to ubiquinol (Ki = 2.38 nM). Therefore, the susceptible site is deduced to be the ubiquinone redox machinery which links the two enzyme activities. Further, ascofuranone in combination with glycerol completely blocked energy production, and potently inhibited the in vitro growth of the parasite. Our findings suggest that ascofuranone might be a promising candidate for the chemotherapeutic agents of African trypanosomiasis.

Animals↗
PubMed1996

New betaclamycin and aclarubicin analogs obtained by prolonged microbial conversion with an aclarubicin-negative mutant.

Microbial conversion of beta-rhodomycinone and aklavinone using an aclarubicin-negative Streptomyces galilaeus mutant afforded new anthracycline antibiotics CG21-C and CG1-C which had a rednosyl-2-deoxyfucosyl-rhodosaminyl trisaccharide residue at C-7 of each added aglycone. They were produced only when a prolonged conversion culture took place. Because the usual conversion products containing a cinerulosyl-2-deoxyfucosyl-rhodosaminyl residue were at first accumulated and then decreased during further cultivation, it was evident that they occurred by the modification of terminal cinerulose. The isolation, purification, and structural determination are described, and cytotoxicity in vitro against cultured L1210 cells and the formation mechanism are discussed.

Aclarubicin↗
PubMed1996

[Usefulness of subcutaneous implantable port with new one-way valve].

Because of the development of the subcutaneous implantable port, intra-arterial infusion chemotherapy for malignant tumor has been performed in safety and it is now possible to choose a more effective method of drug administration. Many problems remain, however. In this study, we investigated the performance of subcutaneous implantable port with a new one-way valve with safety, septum intensity and a back stream of blood. This new port was very safe, with good septum intensity and water backflow. In the performance test with a back stream of water into the catheter, water did not back up into the catheter connecting with the port with the one-way valve, but did so without the one-way valve after releasing a load of 2,000 g from the septum. This suggests that the catheter obstruction is decreased by adding a one-way valve to the port.

Catheterization↗
PubMed1996

[Repair of the gastric tube-right main bronchus fistula after operation for esophageal cancer--treatment by transposition of pedicled pectoralis major muscle flap].

We have experienced a case who showed the gastric tube-right main bronchus fistula. A 51-year-old male complained cough and vomiting suddenly. He underwent esophagectomy and radio-chemotherapy for advanced esophageal cancer 19 months ago. Chest X-ray showed severe pneumonia, and gastroscopy, bronchoscopy and CT scan showed the fistula between the whole stomach esophageal substitute and right main bronchus. After recovery from the pneumonia with the treatment by continuous suction through the naso-gastric tube, operation was performed. The fistula was repaired with transposition of a pedicled pectralis major muscle successfully. After the operation, respiration was performed independently with two ventilators for right and left lung to avoid increasing air way pressure. His postoperative course was uneventful, and he discharged on the 66th postoperative day. The cause of the fistula was considered to be a peptic ulcer due to residual secretion of gastric acid.

Bronchial Fistula↗
PubMed1995

Preservation of the lower esophageal sphincter during total gastrectomy for gastric cancer to prevent postoperative reflux esophagitis.

The lower esophageal sphincter (LES) is usually removed during total gastrectomy to successfully perform a curative operation. In this study, the preservation of the LES in curative total gastrectomy was attempted to reduce the reflux. An experimental study using dogs has revealed that the high-pressure zone of the LES can be preserved by making a resection at the gastroesophageal junction, which thus helps to protect the reflux. A previous clinicopathological study revealed that the LES can be preserved without any fear of recurrence at the resection site, if the tumor is located more than 2.0 cm and 3.0 cm from the gastroesophageal junction to the oral margin in node-negative and -positive cases, respectively. Clinically, 8 patients underwent an LES-preserving total gastrectomy [LES(+) gastrectomy] while 19 had an LES(-) gastrectomy in the same period. Of the five LES(+) cases examined, all showed a high pressure zone, whereas none of the four LES(-) cases examined showed such a high-pressure zone after the operation. Endoscopic examination showed that only one of the seven LES(+) cases but six of nine LES(-) cases revealed esophagitis.

Anastomosis, Surgical↗
PubMed1995

Clinical usefulness of an ATP heat sensitivity test using endoscopic biopsy materials from esophageal cancer patients.

The usefulness of a heat sensitivity test which involved performing an ATP assay on endoscopic biopsy materials for predicting the clinical response to hyperthermia was investigated in esophageal cancer patients. Following in vitro heat treatment of FM3A tumor cells, the heat sensitivity detected by ATPA was significantly correlated with that in the colony-forming assay, and the percent inhibition of the ATP level in the tumor cells was correlated with in vivo tumor growth. The heat sensitivity of the biopsy materials evaluated by ATPA correlated well with that of the resected specimens in 18 esophageal cancer patients, while the clinical response to thermal therapy was well predicted by the heat sensitivity of the biopsy materials evaluated by ATPA in seven of the patients. These results indicate that the heat sensitivity test conducted by performing an ATPA on endoscopic biopsy materials could be a useful indicator for predicting the clinical response to thermal therapy.

Adenosine Triphosphate↗