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Biomedical subjects

H Ohashi

Publications and source records attributed to H Ohashi.

At least 415 records · Page 23Linked to original sources
PubMed1989

[Surgical treatment of interrupted aortic arch in infants under three months of age].

From March, 1982, through March, 1988, 8 infants less than 3 months of age underwent surgical treatment of interrupted aortic arch. Five patients had IAA type A and 3 patients had type B. Seven patients with associated VSD underwent staged operations and 1 infant with aortopulmonary window underwent primary repair off cardiopulmonary bypass. Aortic arch reconstruction was by subclavian aortic anastomosis (6) or large tube graft (8 mm) interposition (2) combined with pulmonary artery banding (5). All seven patients with associated VSD survived the first-stage operation. One patient subsequently underwent pulmonary artery banding, two underwent patch aortoplasty and four patients underwent intracardiac repair and removal of a pulmonary artery band, with six survivors (86%). The operative death occurred in an infant in whom modified Damus-Kaye-Stansel operation was carried out for severe subaortic stenosis, which rerouting all left ventricular blood through VSD and the main pulmonary artery into the ascending aorta and reconstructing right ventricular-distal pulmonary artery connection by a valved external conduit. All six surviving patients are doing well at present (mean follow up of 3 years) without any significant pressure gradient between the ascending and thoracic aorta. Based on these data we conclude: (1) Aortic arch reconstruction and pulmonary artery banding can be reliably performed even in critically ill infants with IAA and isolated VSD. (2) The primary repair will provide better chance of survival in infants with IAA associated with significant LVOTO, truncus arteriosus or aortopulmonary window that do not readily lend themselves to pulmonary artery banding.

Anastomosis, Surgical↗
PubMed1989

Nuclear binding sites for reverse triiodothyronine in human placenta.

It has been generally believed that reverse triiodothyronine (reverse T3, rT3) is biologically inactive. Nevertheless the serum rT3 level is very high in fetal life, when the serum calcium level is higher than in the maternal. For this hypercalcemia in fetal life, there is no convincing evidence that any major calcium regulating hormone is responsible. And the assumption that rT3 may be concerned in active transport of calcium at placenta could be suggested. In this study nuclear protein was isolated from human placenta by extraction with 0.4M KCl buffer and binding studies utilizing radioactive rT3 were carried out. Scatchard analysis presented a curvilinear pattern, suggesting two classes of receptors: One with a association constant (Ka) of 1.14 X 10(8) M-1 and a limited capacity (Bmax) of 32.0 X 10(-15) mol/100 micrograms DNA and the other with Ka = 4.34 X 10(6) and Bmax = 454 X 10(-15). Its relative affinities for several thyroid hormone analogues were calculated. If the affinity for rT3 was assigned l, that for triiodothyronine would be 1/40, thyroxine: 1/63, Triiodothyroacetic acid: 1/18. Sulfhydryl agents affecting these binding characteristics were also studied. The Ka was not substantially changed but the Bmax was notably decreased by dithiothreitol (43%) and 2-mercaptoethanol (26%). In liver nuclei, the binding characteristics of rT3 receptor were analyzed for comparison. In this case only a single class of low affinity-high capacity rT3 binding site with a Ka of 6.69 X 10(6) was detected, a finding which was apparently different from those in placenta.(ABSTRACT TRUNCATED AT 250 WORDS)

Binding Sites↗
PubMed1989

[Thoracoabdominal ectopia cordis with single ventricle and pulmonary stenosis. A case report of successful surgical repair].

A case of thoracoabdominal ectopia cordis with single ventricle and pulmonary stenosis is reported. A cyanotic boy with omphalocele was brought to our hospital soon after his birth and was diagnosed as thoracoabdominal ectopia cordis with single ventricle and pulmonary stenosis. A conservative treatment of omphalocele was performed successfully and a plastic chest shield had been made for him which protected the anterior surface of his chest. He continued to develop in a fairly satisfactory condition and operation was delayed until he was 8 years old when he had severe cyanosis and frequent episodes of headache. The operative procedures were; 1) ascending aorta to main pulmonary artery shunt with EPTFE tube; 2) to bring the heart into the thoracic and abdominal cavity by developing widely the pericardial and diaphragmatic defect behind the heart's preoperative position; 3) to reconstruct the new pericardial sac lying from thoracic to abdominal cavity by covering the heart using EPTFE sheet. This trial of making a new pericardial sac for thoracoabdominal ectopia cordis is not reported so far in the literature. It is expected that the heart has being raised to the thoracic cavity with patient's physical growth after this operation.

Child↗
PubMed1989

[Successful simultaneous repair of tetralogy of Fallot and congenital tracheal stenosis in a 5-year old child].

Congenital cardiac anomaly combined with severe obstructive lesion of airway remains a surgical challenge. A case of 5-year old child with tetralogy of Fallot associated with congenital tracheal stenosis (cartilagenous ring) was reported. The patient had history of cyanosis and stridor since age 3 months and had been hospitalized repeatedly for recurrent respiratory distress. The diagnosis was first established and emergent Blalock-Taussig shunt was carried out during first admission at age 1 year and 7 months. On the fourth admission at age 5 year, a definitive surgical intervention was decided following re-evaluation of the patient by cardiac catheterization, bronchoscopy and bronchography. Trachea and heart were exposed through cervical collar and presternal skin incision and median sternotomy. Tracheal resection and end-to-end anastomosis combined with total correction of tetralogy of Fallot was carried out under cardiopulmonary bypass. Utmost care was paid to avoid contamination during the operation. He was extubated at 9th postoperative day and has been free from symptom 9 months after the operation.

Cardiopulmonary Bypass↗
PubMed1989

[Early and late results of surgical treatment of coarctation of the aorta in infants less than six months of life--including the propriety of pulmonary artery banding].

During an 8-year period, 53 infants less than six months of life underwent repair of coarctation of the aorta (CoA). Preoperatively 58 percent of patients received intensive circulatory and/or respiratory care. The diagnosis was established by echocardiography and counter current aortography via a radial artery in the majority of recent cases and the surgical relief of CoA was effected within 24 hours of the diagnosis. The last 51 patients were managed under the policy of simple repair of the CoA in patients with significant VSD (Group II), with the addition of pulmonary artery banding for patients with complex cardiac lesions with VSD (Group III) or for patients with incremental risk factors in Group II such as prematurity of body weight of less than 1500 gm, other organ anomalies requiring major operation in neonate, pulmonary complications or severe malnutrition. There was no intraoperative death, one (2%) postoperative and five (10%) late deaths among the lost 51 patients. Only one (2%) showed sign of recurrence among 46 patients followed for 16-112 (mean 47) months.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Coarctation↗
PubMed1989

[False aneurysm of the right pulmonary artery--a rare complication of aorto-pulmonary shunt in a patient with tricuspid atresia].

A 12-year-old girl with tricuspid atresia who underwent a side-to-end anastomosis between the ascending aorta and the right pulmonary artery at the age of two months, developed a false aneurysm of the right interlobar trunk artery. The diagnosis was established by angiography, computed tomography and bronchoscopy. Emergency surgical intervention was required because of impending aneurysmal rupture into the right interlobar bronchus. Creation of a left Blalock-Taussig shunt to tide over the anticipated postoperative hypoxemia and right middle and lower lobectomy were carried out successfully. The false aneurysm in this case occurred following an episode of a streptococcal infection and was probably mycotic in origin. But it is possible that the presence of aorto-pulmonary shunt itself might have affected as a predisposing factor for aneurysm formation in this case.

Aneurysm, Infected↗
PubMed1989

A new technique for use of an anomalous subclavian artery for a systemic-pulmonary arterial shunt.

Anomalous subclavian arteries were used as interposition grafts for systemic-pulmonary arterial shunts in three infants and children with good early and long-term results. This is the first report of the use of an anomalous subclavian artery as an interposition graft for a systemic-pulmonary arterial shunt. The advantages and effectiveness of the technique are discussed.

Anastomosis, Surgical↗
PubMed1988

Complete nucleotide sequence and characterization of the 5'-flanking region of mammalian elongation factor 2 gene.

The hamster elongation factor 2 gene was isolated from genomic libraries of diphtheria toxin- and Pseudomonas aeruginosa exotoxin A-resistant cells containing non-ADP-ribosylatable elongation factor 2, and its structure was determined by a combination of restriction endonuclease mapping and DNA sequence analysis. The entire gene is about 6 kilobases long and has 13 exons. Almost all the introns are about 90-200 bases long, except the first and third, which are about 1 kilobase and 400 bases long, respectively. The first exon is processed just after the initiation codon for translation. The promoter of this gene was also characterized. As this gene contains the mutation conferring resistance to diphtheria toxin and P. aeruginosa exotoxin A, introduction of this gene into mammalian cells results in expression of toxin resistance. Using this characteristic, gene expression by deletion mutants of the 5'-flanking region were examined, and results showed that about 60 base pairs upstream of the TATA sequence were most efficient for expression of the elongation factor 2 gene.

Amino Acid Sequence↗
PubMed1988

One Japanese MODY family with severe and progressive microangiopathies.

Recently we investigated maturity-onset diabetes of the young (MODY) with severe and progressive microangiopathies in one Japanese family. The proband was a female who was diagnosed as having diabetes when she was 11 years old, and was controlled without insulin for 9 years. She is now 30 years old and has been suffering from proliferative retinopathy since the age of 20. Her maternal grandfather, mother, uncle, and younger sister are also diabetic with severe microangiopathies. MODY is a concept which was first put forward by Tattersall and Fajans in 1975. It was defined as a form of diabetes diagnosed before the age of 25 years, controlled without insulin for more than 2 years and demonstrating dominant heredity over more than three generations. Most Western papers have reported few microangiopathies in the MODY patient, but our findings run counter to this description.

Adult↗
PubMed1988

Cure of advanced gastric cancer by combined chemotherapy with cisplatinum, mitomycin C, and 5-fluorouracil.

A 55-year-old female, in which an unresectable Borrmann II-type gastric cancer (moderately differentiated adenocarcinoma) extending from vicinity of the cardia to the lower portion of the corpus, with direct invasion into the pancreas and extensive lymph node metastases, confirmed by laparotomy, was treated postoperatively by 3 courses of chemotherapy with cisplatinum in combination with mitomycin C and 5-fluorouracil. A complete response was confirmed by roentgenography and endoscopy, and, at 4 months after the first operation, a total gastrectomy with radical lymphadenectomy was performed successfully. Cancer cells were not detectable histologically in the stomach specimen and in all the lymph nodes removed. One year and 5 months after the second operation she is well, showing no sign of recurrence.

Adenocarcinoma↗
PubMed1988

Exclusive accumulation of Z-isomers of monolignols and their glucosides in bark of Fagus grandifolia.

In addition to Z-coniferyl and Z-sinapyl alcohols, bark extracts of Fagus grandifolia also contain significant amounts of the glucosides, Z-coniferin, Z-isoconiferin (previously called faguside) and Z-syringin. The corresponding E-isomers of these glucosides do not accumulate to a detectable level. The accumulation of the Z-isomers suggests that either they are not lignin precursors or that they are reservoirs of monolignols for subsequent lignin biosynthesis; it is not possible to distinguish between these alternatives. The co-occurrence of Z-coniferin and Z-isoconiferin demonstrate that glucosylation of monolignols can occur at either the phenolic or the allylic hydroxyl groups.

Acetylation↗
PubMed1988

Effects of prolonged exposure to alpha,beta-methylene ATP on non-adrenergic, non-cholinergic excitatory transmission in the rectum of the chicken.

1. Effects of prolonged exposure to alpha,beta-methylene ATP (alpha,beta-Me ATP) on contractions and excitatory junction potentials (e.j.ps) evoked by non-adrenergic, non-cholinergic (NANC) excitatory nerve stimulation have been investigated in the chicken isolated rectum and longitudinal muscle strip from chicken rectum pretreated with atropine (0.5 microM), methysergide (2 microM) and pyrilamine (3 microM). 2. Alpha,beta-Me ATP (20 nM-4 microM) caused a rapid rise in tension of the longitudinal muscle of the isolated rectum preparation which returned to the baseline levels after a few minutes. The magnitude of the contractile response to NANC nerve stimulation was reduced after exposure to the drug. The inhibitory effect was related to the drug concentration; at 4 microM the nerve-mediated contraction was abolished and frequently converted to a relaxation. 3. Adenosine 5'-triphosphate (ATP, 100 microM), bovine neurotensin (2.5 nM) and K+-rich solutions (30 nM and 60 nM) all produced a transient contraction of the isolated rectum preparation. The exposure to alpha,beta-Me ATP (0.2 and 4 microM) also rendered the preparation less sensitive to these stimulant substances. 4. Alpha,beta-Me ATP (0.2 and 4 microM) caused a membrane depolarization in cells of the longitudinal muscle strip. The depolarization reached a peak within 2-3 min after application and then decayed to a steady level that was still more positive than the baseline level. The electrotonic potentials were reduced in amplitude to 44 +/- 8% (n = 7) of the normal amplitude if measured at the peak depolarization produced with 0.2 microM alpha,beta-Me ATP, and to 62 +/- 10% (n = 7) if measured at the steady-state depolarization. With 4 microM, the corresponding percentages were 33 +/- 7% (n = 8) and 55 +/- 7% (n = 8), indicating a decrease in membrane resistance. 5. The e.j.ps in response to field stimulation of the intramural nerves and Remak's nerve stimulation were decreased in amplitude and duration during exposure to alpha,beta-Me ATP (0.2 and 4 microM). 6. The smooth muscle cells regained normal membrane resistance and sensitivity to ATP on washout of alpha,beta-Me ATP (4 microM) more rapidly than the responses to NANC nerve stimulation. 7. It can be argued from the results that the suppression by alpha,beta-Me ATP of the contraction and e.j.p. evoked by NANC nerve stimulation in the chicken rectum, unlike the mammalian preparation described previously, is due mainly to a change in the electrical properties of the membrane of the smooth muscle cells, rather than being due, or only partly due, to desensitization of the purine receptor.

Adenosine Triphosphate↗
PubMed1988

Development before and after hatching of non-cholinergic excitatory innervation to the rectum via Remak's nerve in the fowl.

1. Development of the excitatory innervation to the rectal region of the intestine via Remak's nerve has been investigated in the rectum with Remak's nerve supply isolated from chicken embryos and young chicks aged less than two weeks. 2. Electrical stimulation of Remak's nerve produced a small contraction of the rectum isolated from chicken embryos on the 14th day of incubation (the earliest time examined). The contractile response was inhibited partially or totally by atropine (0.1 micrograms ml-1) but enhanced by physostigmine (0.01 to 0.05 micrograms ml-1), indicating its cholinergic nature. 3. During the embryonic stage, the proportion of the atropine-resistant component in the contractile response increased, and the contractile response became almost entirely atropine-resistant within the first week after hatching. 4. Later after hatching, the contractile response was increased in magnitude by atropine and reduced by physostigmine. 5. It is concluded that the excitatory innervation to the chicken rectum via Remak's nerve is cholinergic at the 14-16th day of incubation and is gradually replaced by a non-cholinergic innervation during embryonic development.

Animals↗
PubMed1988

Membrane potential responses to ATP applied by pressure ejection in the longitudinal muscle of chicken rectum.

1. Changes in membrane potential in response to local application of ATP by pressure ejection from a micropipette were recorded intracellularly from smooth muscle cells of the longitudinal muscle strip of chicken rectum. 2. The local application of ATP produced a membrane depolarization. The depolarizing response increased to a plateau of 33 mV with prolongation of the duration of pressure pulses which determines the amount of ATP ejected. The latency and the time required to reach a peak depolarization were not related to the pulse duration, and the shortest latency was 50 ms. 3. When the application of ATP was repeated at a short interval, the second and subsequent depolarizing responses were suppressed, and their latency and time to reach a peak were also increased; the muscle cells became desensitized to ATP. Recovery from the desensitization occurred slowly over a period of 60 s. 4. Electrotonic potentials decreased in amplitude and time course during an ATP-induced depolarization, indicating a decrease in membrane resistance. 5. The ATP-induced depolarization was longer in the latency than an excitatory junction potential (e.j.p.) elicited by electrical field stimulation of the intramural nerves. The other variables such as amplitude, time to reach the peak and duration could not be matched with those of the e.j.p. at the same time. 6. The e.j.p. decreased in amplitude and duration during the ATP-induced depolarization, and its initial amplitude and duration were restored immediately after termination of the ATP-induced depolarization, as in the case of electrotonic potentials. The ej.ps were recorded in the same manner as the control from the muscle cell which was in a state of desensitization to ATP. 7. The present results provide an argument against the hypothesis that ATP mediates the ej.p. in the rectum of the chicken.

Adenosine Triphosphate↗
PubMed1988

Some membrane properties of the circular muscle of chicken rectum and its non-adrenergic non-cholinergic innervation.

1. Membrane properties and innervation of the circular muscle of chicken rectum were investigated by recording intracellularly electrotonic potentials evoked by passing current, and excitatory and inhibitory junction potentials (EJPs and IJPs) evoked by electrical stimulation of the extrinsic or intrinsic nerves. 2. The membrane potential was -55 +/- 0.6 mV (n = 95). Action potentials of long duration (1.2-4.0 s) discharged spontaneously, or were generated when the membrane depolarization due to either electrotonic potential or EJP reached the threshold. The drug D600 blocked the generation of action potentials. 3. Electrotonic potentials spread fairly well in the longitudinal direction of the muscle fibres but not in the transverse direction. The longitudinal space constant was 1.7 +/- 0.2 mm (n = 10) and the membrane time constant was 205 +/- 21 ms (n = 10). 4. Field stimulation of intramural nerves evoked an EJP followed by a long-lasting IJP (3-12 s in total duration) in most cells, and an EJP alone or an IJP alone in a small number of cells. The EJP and IJP were preserved in the simultaneous presence of atropine and guanethidine, but abolished with tetrodotoxin. 5. Stimulation of Remak's nerve trunk or its branches produced EJPs which were atropine resistant and guanethidine resistant just like the EJP elicited by intramural nerve stimulation. The extrinsic nerve stimulation was ineffective in eliciting IJPs. 6. The EJP amplitude declined in a linear manner as the distance from the stimulating site of intramural nerves was increased. The decline was much greater along the transverse axis than the longitudinal axis of circular muscle fibres. 7. The reversal potential for the EJP was estimated by extrapolation to be about - 15.3 +/- 0.3 mV (n = 7). 8. Apamin did not inhibit the IJP. During the hyperpolarization of a single IJP or summed IJPs, electrotonic potentials remained unchanged or slightly decreased in amplitude.

Action Potentials↗
PubMed1988

Molecular cloning of the penicillin G acylase gene from Arthrobacter viscosus.

Penicillin G acylase was purified from the cultured filtrate of Arthrobacter viscosus 8895GU and was found to consist of two distinct subunits with apparent molecular weights of 24,000 (alpha) and 60,000 (beta). The partial N-terminal amino acid sequences of the alpha and beta subunits were determined with a protein gas phase sequencer, and a 29-base oligonucleotide corresponding to the partial amino acid sequence of the alpha subunit was synthesized. An Escherichia coli transformant having the penicillin G acylase gene was isolated from an A. viscosus gene library by hybridization with the 29-base probe. The resulting positive clone was further screened by the Serratia marcescens overlay technique. E. coli carrying a plasmid designated pHYM-1 was found to produce penicillin G acylase in the cells. This plasmid had an 8.0-kilobase pair DNA fragment inserted in the EcoRI site of pACYC184.

Amidohydrolases↗
PubMed1988

A plasma inhibitor of sodium and potassium activated adenosine triphosphatase in patients with essential hypertension.

The purpose of this study is to evaluate the plasma Na, K-ATPase inhibitor (NKI) in patients with essential hypertension and to compare the mode of its biochemical actions on the Na, K-ATPase with that of ouabain. Plasma NKI was extracted through a reversed-phase cartridge column and its inhibitory action on hog brain Na, K-ATPase was measured in vitro. Plasma NKI activity was significantly greater in patients with essential hypertension (44 +/- 2.8% (S.E.), n = 28, p less than 0.01) than in normotensive controls (25 +/- 2.4%, n = 21). No significant correlation was demonstrated between the values of plasma NKI and mean arterial pressure in either group. Both plasma NKI and ouabain showed a dose-dependent inhibition on the Na, K-ATPase reaction. An action of ouabain was competitively antagonized by increased concentration of potassium in the reaction mixture, while plasma NKI showed a constant inhibition on the Na, K-ATPase independently of potassium concentrations. The action of plasma NKI was of rapid onset and linear with time, while ouabain showed a delayed onset of the reaction over 30 sec, followed by a progressively increasing inhibition on the enzyme reaction. Finally, the inhibitory action of plasma NKI on Na, K-ATPase was completely abolished in the presence of bovine serum albumin even at the concentration of 500 micrograms/ml in the reaction mixture, which did not have any influence on the actions of ouabain. To sum up, the results showed a markedly different nature of plasma NKI from ouabain in the mode of biochemical actions on the Na, K-ATPase in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗