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Biomedical subjects

H Ohashi

Publications and source records attributed to H Ohashi.

At least 397 records · Page 22Linked to original sources
PubMed1990

[Staged operation for supravalvular aortic stenosis syndrome associated with severe multiple peripheral pulmonary stenoses: a case report and surgical methods].

Successful surgical correction of supravalvular aortic stenosis (SAS) syndrome associated with severe peripheral pulmonary stenosis by a staged approach in a 6-year-old boy is reported. Right ventriculogram demonstrated bilateral severe peripheral pulmonary stenoses and cardiac catheterization revealed severe pressure gradient of 94 mmHg between the trunk of pulmonary artery and right and left peripheral pulmonary arteries, respectively. Bilateral severe peripheral pulmonary stenoses were relieved successfully by staged operations. Initially, a stenotic portion of the right pulmonary artery and its bifurcation was removed and a DeBakey Knitted Dacron graft was interposed between the right pulmonary artery and the peripheral pulmonary artery which was enlarged by arterioplasty. Nine days later, stenosis of the left peripheral pulmonary artery was relieved by arterioplasty using a Rygg patch. Finally, 8 months after the initial operation, the patient underwent definitive repair of SAS by extended aortoplasty. The postoperative course of the patient was uneventful. Our experience indicates that in the surgical treatment of the patient with SAS and associated severe multiple peripheral pulmonary stenoses, a staged approach, that is initial staged repair of the bilateral pulmonary stenoses by arterioplasty through thoracotomy followed by definitive intracardiac repair of SAS, is the procedure of choice.

Aortic Valve Stenosis↗
PubMed1990

Concomitant repair of congenital tracheal stenosis and complex cardiac anomaly in small children.

Severe obstructive lesion of the trachea combined with complex congenital cardiac anomaly has generally been regarded as a fatal disease. Herein we report the successful concomitant repair of severe tracheal stenosis and complex cardiac anomaly with the use of cardiopulmonary bypass in two cases. The first patient was a 5-year-old boy with tetralogy of Fallot associated with a localized intrathoracic tracheal stenosis caused by complete cartilaginous rings. Tracheal resection and end-to-end anastomosis combined with total correction of tetralogy of Fallot was performed with the aid of cardiopulmonary bypass. The second patient was a 5-month-old girl with a pulmonary artery sling, scimitar syndrome, and extensive tracheal stenosis. The patient underwent definitive correction of cardiac lesions and complete tracheal reconstruction with a cartilaginous graft with the aid of cardiopulmonary bypass. Utmost care was paid to avoid contamination during the operation. Both of the patients are doing well at present without any signs of complication, 2 years 5 months and 1 year 10 months after the operation, respectively. We advocate concomitant repair of both lesions, with cardiopulmonary bypass, in the surgical managements of infants and small children who have a difficult and otherwise fatal combination of complex congenital cardiac anomaly and severe intrathoracic tracheal stenosis.

Cardiopulmonary Bypass↗
PubMed1990

[Clinical evaluation of various methods of myocardial protections during open heart surgery in infants with ventricular septal defect and severe pulmonary hypertension].

The effectiveness of various methods of myocardial protection were evaluated retrospectively in 59 infants less than 12 months of age who underwent open heart surgery for ventricular septal defect with severe pulmonary hypertension. Intermittent aortic clamping and electrically induced ventricular fibrillation (EF) were employed in 13 infants (Group I), and potassium induced cold cardioplegia and topical cardiac cooling (TC) were used in 14 infants (Group II). Six infants in Group II had additional EF after declamping of the aorta (Group II-A) but the rest of Group II infants did not have any EF (Group II-B). Profound hypothermia and circulatory arrest were utilized in 17 infants (Group III). Cold blood cardioplegia with TC were used in 15 infants (Group IV). Moderate hypothermia were used during cardiopulmonary bypass in Group I, II and IV. The operative mortality for Group I was 15% and was 0% for Group II, III and IV. The incidence of spontaneous resumption of cardiac beat following declamping of the aorta were 33.3, 0, 100, 94.1, 93.3% for Group I, II-A, II-B, III and IV respectively. The urinary output obtained in the postoperative 72 hours was significantly lower in Group I than in Group II, III and IV (Group I less than II less than IV less than III).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiopulmonary Bypass↗
PubMed1989

Simplified cosmid vectors for gene transfer to cultured mammalian cells: isolation of the gene for elongation factor 2 from the mouse.

We constructed a series of cosmid vectors that carry two tandemly arranged lambda cos and mammalian selective markers. We achieved cloning efficiencies of 1-3 x 10(7) and greater than 10(6) colony-forming units per microgram of insert, using a cloned 42-kb BamHI fragment and Sau3AI fragments of 40-50 kb from mouse genomic DNA, respectively. The modified Ca.phosphate coprecipitation method [Ishiura et al., Mol. Cell. Biol. 2 (1982) 607-616] considerably improved the efficiency of gene transfer of cosmids into cultured mammalian cells: when genes encoding thymidine kinase from herpes simplex virus type 1 and aminoglycoside 3'-phosphoribosyltransferase from Tn5 were selected, the efficiencies of gene transfer into mouse L cells were about 10(-6). The mouse genome contains one copy of the functional gene for elongation factor 2 (EF2) per haploid genome and multiple copies of the EF2-related gene. We isolated a cosmid that carried functional full-length mouse EF2 from a cosmid library of L-cell genomic DNA, by colony hybridization and subsequent gene transfer of candidate cosmids into human 143B cells.

Animals↗
PubMed1989

Phage particle-mediated gene transfer of recombinant cosmids to cultured mammalian cells.

An efficient procedure for the introduction of recombinant cosmids into cultured mammalian cells consists of the following steps. Cosmids were packaged, in vitro, into lambda phage particles and transduced into Escherichia coli hosts lysogenized with thermo-inducible lambda c Its phage. The introduced cosmids were repackaged into phage particles in the thermo-induced hosts. The efficiency of such in vivo cosmid packaging was further improved by construction of pTC vectors that carried three cohesive end sites (cos) of phage lambda, arrayed in tandem. Two types of cosmids, in almost equal numbers (i.e., cosmids with one cos and cosmids with two cos), were obtained from a cosmid library constructed with pTC vectors. The efficiency of packaging in vivo of cosmids with two cos, was found to be 7-20 times higher than that of corresponding cosmids with only one cos. Use of a high-copy-number derivative of pTCl further improved the phage yield by 20- to 30-fold. The packaged cosmids, which carried the thymidine kinase-encoding gene of herpes simplex virus type 1 as a selective marker, were introduced into mouse Ltk- cells with an efficiency of 10(-5), by the phage transfer method [Ishiura et al., Mol. Cell. Biol. 2 (1982) 607-616].

Animals↗
PubMed1989

Efficient simplified cosmid cloning: construction and characterization of cosmid vectors that carry the two cohesive end sites of lambda phages arrayed in tandem.

We constructed a series of cosmid vectors that carry the two cohesive end sites (cos) of lambda phage, arrayed in tandem, which enabled us to clone fragments of genomic DNA of up to 50 kb without a vector background. An equimolar mixture of the left and right vector arms of equal length was prepared from the vector DNA, simply by treating the DNA sequentially with three enzymes, restriction enzyme PvuII, alkaline phosphatase, and restriction enzyme BamHI (or BglII), without purification by agarose gel electrophoresis. After phenol extraction and ethanol precipitation, the equimolar mixture of the vector arms, which carried a single cos oriented from left to right, was directly ligated with insert DNA without further manipulation. We established conditions for cosmid cloning, using two kinds of DNA fragment of 40-50 kb, prepared from mouse L cell genomic DNA, as insert DNAs, namely, three cloned BamHI fragments and Sau3AI fragments, size-selected on a sucrose density gradient. The most important parameters affecting the cloning efficiency were the quality of the insert DNA and the molar ratio of the insert and vector arms. We achieved cloning efficiencies of 3.6 X 10(6)-1.3 X 10(7) colony forming units (cfu)/micrograms of insert DNA and 1.7 X 10(5)-1.0 X 10(6) cfu/micrograms of insert DNA, using the cloned BamHI fragments and the Sau3AI fragments, respectively. We examined more than 5000 clones and found that they all contained insert DNA.

Animals↗
PubMed1989

Activation of protein kinase C by elevation of glucose concentration: proposal for a mechanism in the development of diabetic vascular complications.

Hyperglycemia is believed to be the major cause of diabetic vascular complications involving both microvessels and arteries as in the retina, renal glomeruli, and aorta. It is unclear by which mechanism hyperglycemia is altering the metabolism and functions of vascular cells, although changes in nonenzymatic protein glycosylation and increases in cellular sorbitol levels have been postulated to be involved. Previously, we have reported that the elevation of extracellular glucose levels with cultured bovine retinal capillary endothelial cells causes an increase in protein kinase C (PKC) activity of the membranous pool with a parallel decrease in the cytosol without alteration of its total activity. Now we demonstrate that the mechanism for the activation of PKC is due to an enhanced de novo synthesis of diacylglycerol as indicated by a 2-fold increase of [14C]diacylglycerol labeling from [14C]glucose. The elevated diacylglycerol de novo synthesis is secondarily due to increased formation of precursors derived from glucose metabolism; this formation is enhanced by hyperglycemia as substantiated by elevated [3H]glucose conversion into water. This effect of hyperglycemia on PKC is also observed in cultured aortic smooth muscle and endothelial cells and the retina and kidney of diabetic rats, but not in the brain. Since PKC in vascular cells has been shown to modulate hormone receptor turnover, neovascularization in vitro, and cell growth, we propose that this mechanism of enhancing the membranous PKC activities by hyperglycemia plays an important role in the development of diabetic vascular complications.

Animals↗
PubMed1989

Expression of the Arthrobacter viscosus penicillin G acylase gene in Escherichia coli and Bacillus subtilis.

The penicillin G acylase gene cloned from Arthrobacter viscosus 8895GU was subcloned into vectors, and the recombinant plasmids were transferred into Escherichia coli or Bacillus subtilis. Both E. coli and B. subtilis transformants expressed the A. viscosus penicillin G acylase. The enzyme activity was found in the intracellular portion of the E. coli transformants or in the cultured medium of the B. subtilis transformants. Penicillin G acylase production in the B. subtilis transformants was 7.2 times higher than that in the parent A. viscosus. The A. viscosus penicillin G acylase was induced by phenylacetic acid in A. viscosus, whereas the enzyme was produced constitutively in both the E. coli and B. subtilis transformants carrying the A. viscosus penicillin G acylase gene.

Amidohydrolases↗
PubMed1989

Enhancing effect of suspended particulate matter on the IgE antibody production in mice.

Suspended particulate matter (SPM), suspended in the polluted environmental atmosphere, are perpetually inhaled into the human body and are considered to have profound effects on human health. This study investigated the enhancing effect of SPM on the IgE antibody production in mice. The IgE antibody responses in mice immunized with intranasal administration of ovalbumin (OA) plus SPM at 3-week intervals were higher than responses in the animals immunized with OA alone. When the dose of OA administered as an antigen was 0.25 microgram, the time course and magnitude of enhancement by SPM was comparable to those by killed Bordetella pertussis, a common adjuvant. SPM had an enhancing effect on IgE antibody production even in a small dose such as 0.25 microgram administered at 3-week intervals. The possibility cannot be excluded that the natural exposure of humans to SPM in the environmental atmosphere may explain the high prevalence rate of allergic rhinitis caused by pollens in polluted districts in Japan.

Adjuvants, Immunologic↗
PubMed1989

Possible role of plasma neurotensin in regulating the excitatory neural control of the rectum of the fowl.

Effects of neurotensin (NT) applied via the blood vessel on the responses to stimulation of Remak's nerve (RNS) were investigated in the chicken isolated and perfused rectums. NT (5 ng-2 micrograms/ml) produced a concentration-dependent inhibition of the constituent contraction but not relaxation of the responses to RNS. In addition, high concentrations of NT (over 80 ng/ml) produced a contraction of the rectal muscle. Propranolol, a beta-adrenoceptor blocking agent, and guanethidine, an adrenergic neurone blocking agent, were able to reduce the inhibitory effect of NT on the response to RNS while potentiating the contractile effect of NT on the rectal muscle. NT (0.1 and 1 microgram/ml), like norepinephrine, decreased the flow rate of perfusate from the isolated rectum which was perfused at a constant pressure. Guanethidine enhanced norepinephrine-induced vasoconstriction, and phentolamine, an alpha-adrenoceptor blocking agent, plus propranolol was able to abolish it. Either of these prior applications resulted in a small but significant reduction of NT-induced vasoconstriction. These findings suggest that NT in plasma may function as a circulating hormone to exhibit an inhibitory action on the excitatory neural input to the rectum in the chicken, and that catecholamine release from adrenergic nerve terminals by NT may account for some but not all of the activity.

Animals↗
PubMed1989

Functional relationship between platelet alpha 2-adrenoceptors and sympathetic nerve activity in man.

Functional relationships between platelet alpha 2-adrenoceptors and sympathetic nerve activity were studied in patients with essential hypertension (n = 23), primary aldosteronism (n = 10), and normal subjects (n = 12). The maximum number of binding sites (Bmax) and the dissociation constant (Kd) of 3H-yohimbine on platelet membranes and resting plasma norepinephrine (NE) were similar among these groups of subjects. In all subjects combined, Bmax values were correlated positively (r = 0.471, p less than 0.01) to resting plasma NE and negatively (r = -0.531, p less than 0.01) to the changes in plasma NE when subjects were moved from lying to standing. A 2-4 week treatment with guanabenz or bethanidine induced a parallel fall of both Bmax and plasma NE, whereas administration of reserpine caused a similar fall of plasma NE but Bmax remained unchanged. Kd values were not changed after any of these treatments. The results support the view that platelet alpha 2-adrenoceptor density is functionally regulated in parallel with sympathetic nerve activity rather than plasma NE per se. This hypothesis seems quite reasonable when it is extended to the presynaptic alpha 2-adrenoceptors; otherwise, the negative feedback function on NE release should be lessened and contradictory to its physiological role.

Adult↗
PubMed1989

[Translumbar radical nephrectomy of renal cell carcinoma].

We invented a new surgical approach to the kidney through the flank to perform a radical nephrectomy for renal cell carcinoma. With the patient in usual lateral decubitus position keeping the dorsum vertical to the operating table, a skin incision is made over the XII rib from the posterior axillary line to the lateral edge of the rectus muscle. After the tip of XII rib is resected by about 5 cm, the retroperitoneal space is entered. Blunt dissection of the posterior aspect of Gerota's fascia from fasciae of the quadratus lumborum and psoas muscle is easily carried out with a liver retractor or intestinal spatula. The pulsating renal artery can be identified through Gerota's fascia when the renal hilus is exposed. Following ligation and division of the artery, renal vein is exposed. On the left side, adrenal, gonadal and occasionally lumbar veins are also ligated and severed in addition to the renal vein. Then, the kidney in Gerota's fascia is removed en bloc with perinephric adipose tissue and adrenal gland. Of 21 patients with renal cell carcinoma seen during 1 year and 3 months from June 1987, 11 underwent this operation, and other 10 patients transperitoneal radical nephrectomy because of the possible tumor extension into the renal vein, inferior vena cava or adjacent organ, the severe spinal deformity or metastases and the necessity of additional surgical procedures for concomitant benign intraperitoneal diseases. The blood loss was smaller and operating time was shorter significantly in the translumbar group than the evaluable transperitoneal group. None of those in the translumbar group received blood transfusion. As complications, pneumothorax due to pleural injury during operation and postoperative incisional hernia occurred each in one patient, but no other serious one was found. From the above results, this approach seems to be one of choices for the surgical treatment of renal cell carcinoma, as long as the tumor is not likely to extend to adjacent organs, ipsilateral nodes or the inferior vena cava.

Adult↗
PubMed1989

[Effects of supplementation with branched-chain amino acids on protein-nutritional status in rats treated by carbon tetrachloride].

A study was conducted to investigate effects of oral supplementation with branched-chain amino acids (BCAA) on protein-nutritional status in rats with liver cirrhosis. Liver cirrhosis was induced in male strain Sprague-Dawley rats by simultaneously administrating carbon tetrachloride (500 mg/kg, twice a week, intracutaneously) and phenobarbital (0.05% in drinking water, ad libitum) for 30 weeks. Following treatment with carbon tetrachloride and phenobarbital, cirrhotic rats received oral supplementation of BCAA with varying ratio among isoleucine (Ile), leucine (Leu) and valine (Val), or with varying content of total BCAA in the diet (Final content of total nitrogen was kept consistent by addition of glutamine). Nutritional efficacies of diets as described above were evaluated employing those protein-nutritional parameters as nitrogen balance and plasma levels of total protein, albumin and free neutral amino acids. Following results were obtained: 1. Compositional ratio of Ile:Leu:Val at 1:2:1.2 or at 2:1:1 was found to be more effective on diets which contained ILe:Leu:Val at 1:1:2 or either Val, Ile or Leu alone. 2. As to content of total BCAA in the diet (0, 2.5, 5, 10%), supplementation level of 2.5% was found to be most appropriate in terms of effects on nitrogen balance and on plasma protein concentration. In conclusion, 2.5% BCAA in the diet with the ratio of Ile:Leu:Val at 1:2:1.2 or 2:1:1 seems to be recommended to improve the impaired protein-nutritional status in liver cirrhosis.

Amino Acids, Branched-Chain↗
PubMed1989

[Surgical repair of scimitar syndrome by direct anastomosis between right pulmonary vein and left atrium].

A surgical case of 8-year-old boy with scimitar syndrome is presented. The patient was admitted to the hospital because of exertional dyspnea and underdevelopment. Cardiac catheterization revealed a large amount of left to right shunt and O2 step up at the level of the inferior vena cava below the diaphragm. Angiography showed that the pulmonary vein draining the right lower lobe pierced the diaphragm and emptied into IVC. At operation the right pleural cavity was entered and a large anomalous pulmonary vein trunk was found which headed downward and medially and eventually entered in the diaphragm. A direct anastomosis between the scimitar vein and left atrium was made. To avoid kinking or stenosis of this vein, the parenchyma of the right lung (S7) was divided to create a passway of the vein. Anastomosis was performed without excessive tension or kinking on it. We conclude that the method applied in this case might be a procedure of choice for the repair of scimitar syndrome especially when there is no associating atrial septal defect or scimitar vein drains into IVC at the level lower than hepatic vein.

Anastomosis, Surgical↗