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Biomedical subjects

T Horiuchi

Publications and source records attributed to T Horiuchi.

At least 469 records · Page 26Linked to original sources
PubMed1986

Blood detoxification by membrane plasma filtration.

The recognition of macromolecule abnormalities in various metabolic or immunologic related disease states has led to the use of plasma exchange for therapeutics. Limitations of plasma exchange, however, exist. Membrane plasma filtration provides a practical alternative. Solute removal can be made selective by the choice of operating conditions as temperature and the selection of the membrane/module design. The optimal temperature range is a function of the plasma type, solute concentrations and membrane system. Operation at below physiologic temperature (cryofiltration) is particularly suited for the removal of cold aggregative solutes, while operation at near or above physiologic temperature is more suited for the separation of solutes having large size differences at normal physiologic temperature. Membrane filtration is simple and safe to perform, is more selective than plasma exchange, does not require plasma product infusion and is more versatile than selective sorption in its applications.

Blood↗
PubMed1985

The polymerase subunit of DNA polymerase III of Escherichia coli. I. Amplification of the dnaE gene product and polymerase activity of the alpha subunit.

The Escherichia coli dnaE gene, which encodes the alpha subunit of DNA polymerase III (pol III) holoenzyme, has been cloned in a plasmid containing the PL promoter of phage lambda and thermally induced to overproduce the alpha subunit. In cells carrying this plasmid (pKH167), the alpha subunit was amplified, after heat induction, to a level of about 0.2% of the total cellular protein. Polymerase activity was assayed in three ways: (i) gap-filling by pol III holoenzyme and subassemblies of it, (ii) the extensive replication of a primed, single-stranded DNA circle only by pol III holoenzyme, and (iii) complementation of a crude, inactive pol III holoenzyme (temperature-sensitive dnaE mutant fraction) in replication of a primed, single-stranded DNA circle. Amplification of the alpha subunit raised the polymerase level 10-fold in assay (i), indicative of the dependence of pol III gap-filling activity on this polypeptide; pol III holoenzyme activity remained unaffected (assay (ii)), but the complementation activity was raised 5-fold (assay (iii)). Thus, the elevated alpha subunit (free or in a subassembly form) can substitute in vitro for a defective alpha subunit in pol III holoenzyme, but cannot increase the in vivo level of about eight pol III holoenzyme molecules per cell. This low level of pol III holoenzyme is fixed in wild type cells (bearing no plasmid) despite the presence of a 5-fold excess of the alpha subunit, as inferred from the various assays. These results suggest that the low level of pol III holoenzyme is determined by a factor or factors other than the level of the alpha subunit.

Bacteriophage lambda↗
PubMed1985

Frozen section diagnosis of hypertensive pulmonary vascular changes at surgery for congenital heart anomalies.

Frozen sections of lung biopsy were prepared in 30 cases of congenital heart anomalies with pulmonary hypertension, and evaluation of severity of the pulmonary vascular changes was made during the surgery. Statistically, significant differences was not found between the diagnosis made by frozen sections and those made by paraffin sections. It is concluded that rapid and accurate diagnosis of pulmonary vascular changes can be made by means of frozen section diagnosis. This method will prove to be clinically important by assisting during operation in rapid assessment of indication for total correction of congenital heart anomalies.

Child↗
PubMed1985

Clinical thermofiltration: initial application.

The first clinical thermofiltration procedures (plasma filtration near or above normal physiologic temperature) were performed on a secondary hypercholesterolemia patient. The intent of this filtration scheme is the selective removal of low density lipoproteins (LDL) and maintenance of high density lipoproteins (HDL) and other essential plasma proteins including albumin. The EVAL 4A filter, at a filtration temperature of 37 degrees C, was selected for on-line thermofiltration. The sieving coefficients of LDL + very low density lipoproteins (VLDL) cholesterol, HDL cholesterol, and albumin were 0.02, 0.75, and 0.78, respectively. These results are comparable to in vitro filtration tests using the plasma of the same patient. This system is simple to apply and does not require replacement solution. Compared with plasma exchange, a high return of HDL and other essential plasma solutes can be returned to the patient by this method.

Adult↗
PubMed1985

Pulmonary changes in congenital heart disease with Down's syndrome: their significance as a cause of postoperative respiratory failure.

Biopsy or necropsy specimens of lung from 28 patients with congenital heart disease and Down's syndrome were studied to establish the cause of the postoperative respiratory failure often seen in such cases. Changes in lungs seen after operation included interstitial emphysema and overdistension of peripheral air spaces, associated with hypoplastic alveoli and deficient elastic fibres in the alveolar wall. In specimens taken before operation alveolar hypoplasia was common but interstitial emphysema or overdistension of lower airways was found only rarely. Findings suggest that alveolar hypoplasia is characteristic of Down's syndrome and that distension of peripheral air spaces or interstitial emphysema was due to artificial inflation of the lung during surgery. The severity of the lesions correlated significantly with the duration of artificial respiration and with the severity of the respiratory failure. Hypoplastic lung tissue in patients with Down's syndrome appears to be more susceptible to mechanical stress, and this is likely to be the cause of postoperative respiratory failure.

Child↗
PubMed1985

Mechanism of action of aldosterone release by prostaglandin E in isolated rat adrenal glomerulosa cells.

The effect of prostaglandin E (PGE) on aldosterone release and the mechanism of action of PGE in mediating the release of aldosterone were studied using isolated rat glomerulosa cells. PGE1 stimulated aldosterone release in a dose-dependent fashion at concentrations between 10(-8) and 10(-6) M and caused approximately a two-fold increase over the basal aldosterone level at 10(-6) M. A significant and dose-dependent increase in cAMP production was also produced by PGE1 at concentrations greater than 10(-8) M. Aldosterone release induced by 10(-7) M or 10(-6) M PGE2 was significantly reduced by a competitive receptor blocking PG-antagonist, SC 19220 (10(-7) M), but not affected by (Sar1, Ileu8)-angiotensin-II (A-II), a competitive inhibitor of A-II. PGE-stimulated aldosterone release was almost completely abolished by depleting the extracellular Ca2+ by EGTA, or by verapamil, a Ca2+-channel blocker or W-7, a calmodulin inhibitor. These findings suggest that PGE stimulates aldosterone release through the membrane receptor binding and activation of adenylate cyclase and that Ca2+-calmodulin system plays an essential role in mediating the steroidogenic action of PGE in the adrenal glomerulosa cells. However, the physiological significance of PGE in the regulation of aldosterone secretion remains to be elucidated.

ADP-Ribosylation Factors↗
PubMed1985

Musculoelastosis: a change of small pulmonary arteries found in a case with atrial septal defect and pulmonary hypertension.

Interesting findings were obtained in the lung biopsy of a 46 year old female patient with secundum atrial septal defect and pulmonary hypertension. In the intima of small pulmonary arteries, there were a marked increase in elastic fibers and marked proliferation of longitudinal smooth muscle cells. The vascular lumen was markedly stenotic, but reconstruction of small pulmonary arteries indicated that all vascular lumina were patent. The case was accordingly diagnosed as operable and closure of atrial septal defect was undertaken. Three years postoperatively, the patient is well with much improved condition and lowered pulmonary arterial pressure was demonstrated by cardiac catheterization. This case had apparently serious vascular lesions due to severe intimal thickening which we labeled "musculoelastosis", but it was found that such thickening alone did not cause peripheral pulmonary arterial occlusion. It is therefore thought to be a benign pulmonary vascular condition.

Diabetic Angiopathies↗
PubMed1985

Mustard procedure for simple transposition of the great arteries.

From May 1980 through April 1982, 9 patients underwent the Mustard operation for simple transposition of the great arteries (simple TGA) at the Tohoku University Hospital, Sendai. There was no early postoperative death, although one patient was lost with pulmonary venous obstruction in the late postoperative period. No pulmonary venous obstruction occurred since the introduction of expanded polytetrafluoroethylene (EPTFE) intraatrial baffle. Normal sinus rhythm has been preserved in all patients since direct, high superior vena cava cannulation was adopted. Postoperative hemodynamic study at an average 12 months after surgery revealed normal right ventricular function at rest. Work-function curve which is related to the right ventricular end-diastolic pressure and minute work index revealed good response of the right ventricle in two of three patients after methoxamine infusion test. All late survivors are acyanotic and clinically well. The Mustard procedure has dramatically improved the survival rate and quality of life for those with simple TGA. Presently, we continue to utilize the Mustard procedure for simple TGA until the superiority of other operations are demonstrated.

Cardiac Output↗
PubMed1985

The importance of colloid osmotic pressure during open heart surgery in infants.

Fifty-five infants with transposition of the great arteries and with total anomalous pulmonary venous return underwent intracardiac repair under combined surface/perfusion hypothermia and total circulatory arrest in 1975 to 1983. Although cardiopulmonary bypass (CPB) time is limited when hypothermic circulatory arrest is employed, fluid balance derangement is one of the major postoperative complications. Fluid balance at the end of CPB averaged +299.5 ml (+63.4 ml/kg) when hemodilution with lactated Ringer's was utilized (Group A). Since colloid osmotic pressure (COP) plays an important role in regulating fluid balance, colloid hemodilution prime (whole blood and plasma) was employed in the last 3 years (Group B). COP and total protein concentration during CPB with colloid prime were maintained at around 19 mmHg and 5 g/100 ml, respectively. In Group B, fluid balance at the end of CPB averaged +81.1 ml (+16.3 ml/kg) and was significantly less than in Group A (p less than 0.01). The ICU stay period for survivors in Group B (average 10.9 days) was reduced to half the period in Group A (average 20.6 days) (p less than 0.05). The mortality rate in Group A was 42%, whereas 23% in Group B. It was concluded that well-maintained COP levels during CPB with colloid hemodilution prime reduced fluid accumulation in the body and made patient care easier following open heart surgery in infants.

Cardiopulmonary Bypass↗