Biomedical subjects

A Kohyama

Publications and source records attributed to A Kohyama.

At least 37 records · Page 2Linked to original sources

PubMed1994

[Effects of NaHCO3 on cardiac function and metabolism during hypoxic metabolic acidosis--2: Rapid infusion of NaHCO3].

The effects of 1M sodium bicarbonate (NaHCO3) on cardiac function and myocardial metabolism during hypoxia were compared with those of 1M sodium chloride (NaCl) in anesthetized dogs. Metabolic acidosis was induced with inhalation of low fraction of oxygen (9%) for 2 hours. NaHCO3 (n = 9) or NaCl (n = 10) was infused intravenously in a half dose of 0.2 x body weight x base excess mEq in 30 seconds. This treatment was repeated five minutes later. In NaHCO3 group; with first infusion, both blood and intramyocardial pH increased. Left ventricular pressure (LVP) and maximum rate of rise of LVP (LV dP/dt max) were unchanged. Cardiac index (CI) tended to increase, while left ventricular end-diastolic pressure (LVEDP) and LVEDP/LVP increased significantly. In five dogs in which myocardial glucose uptake increased, LV dP/dt max increased. With the second infusion, inspite of the increase of blood and intramyocardial pH, LVP and LV dP/dt max decreased significantly compared with the preceding values. In NaCl group, with first infusion, blood and intramyocardial pH decreased. CI increased significantly, while LVP and LV dP/dt max tended to decrease, and LVEDP and LVEDP/LVP increased significantly. After the second infusion, myocardial contractility was depressed significantly. In both groups, blood lactate (LA) level increased significantly, especially with NaHCO3 infusion. LV dP/dt max correlated significantly with LA in NaCl group (r = -0.614, P < 0.001). However, in NaHCO3 group, LV dP/dt max did not correlate with LA. Blood glucose level (r = 0.612, P < 0.001) and myocardial glucose uptake (r = 0.718, P < 0.001) correlated significantly with LV dP/dt max in NaHCO3 group.(ABSTRACT TRUNCATED AT 250 WORDS)

Acidosis, Respiratory↗

PubMed1993

[Effect of cardiopulmonary bypass on the renal tubular cell--the importance of the changes in the ratio of creatinine to blood urea nitrogen].

We examined the effect of cardiopulmonary bypass on the renal tubular cell in 19 adult patients undergoing cardiac surgery. The ratio of creatinine to blood urea nitrogen (BUN/Cr) decreased in the early period of cardiopulmonary bypass, because of increased serum creatinine and unchanged blood urea nitrogen. N-acetyl-beta-D-glucosaminidase (NAG) index in the intra- and postbypass period was higher than that in the preoperative period. Creatinine clearance (CCr) on the 7th postoperative day and the difference of BUN/Cr between preoperative period and 30 min after initiation of cardiopulmonary bypass (delta BUN/Cr 30 min) correlated significantly with the postoperative NAG index. The results suggest that cardiopulmonary bypass impaired the renal tubular cell, and renal tubular injury deteriorated the glomerular filtration in the postbypass period, and that creatinine production increased in the early period of cardiopulmonary bypass. delta BUN/Cr 30 min may predict the intraoperative renal tubular injury.

Acetylglucosaminidase↗

PubMed1993

[Is thoracic epidural anesthesia beneficial to myocardial ischemia?--Influence of hemodynamics].

The effects of thoracic epidural anesthesia (TEA) on regional myocardial blood flow (RMBF) and hemodynamics were evaluated in open-chest dogs with coronary artery stenosis. In the 6 dogs with pressure-rate quotients (PRQ) of greater than 0.8, TEA caused a significant increase of the ratio of endocardial to epicardial RMBF in the ischemic region and tended to increase the ratio of RMBF in the ischemic to normal area, resulting in improved myocardial ischemia. There was no reduction of myocardial ischemia in the 11 dogs with PRQ of less than 0.8. The hemodynamic effects determine whether TEA is favorable for the ischemic heart or not. It appears that PRQ is useful as an indicator of myocardial oxygen balance during TEA.

Anesthesia, Epidural↗

PubMed1993

[Left ventricular function during hypoxia--II: Effects of intramyocardial pH].

We investigated the effects of intramyocardial acidosis on cardiac function during hypoxia in mongrel dogs (n = 50). Intramyocardial pH in subendocardium of left ventricle was measured continuously using a pH electrode. During hypoxia (PaO2 = 20 mmHg) caused by inhalation of low oxygen fraction, intramyocardial pH decreased significantly following initial enhancement. Intramyocardial pH correlated significantly with arterial pH, base excess, lactic acid (LA) levels, coronary venous PcO2, and coronary venous-arterial PcO2 difference. There were significant correlations between intramyocardial pH with maximum rate of rise of left ventricular pressure (LV dp/dt max), left ventricular end-diastolic pressure (LVEDP), LVEDP/LVP and the time constant of exponential isovolumic left ventricular pressure fall. High arterial LA levels tended to cease myocardial LA uptake and production, turning LA balance into zero. LV dp/dt max was low in such a condition. Myocardial LA production decreased intramyocardial pH, but LV dp/dt max was maintained at high levels of LA production. These observations suggest that myocardial LA production maintains left ventricular function with the increase of ATP by acceleration of anaerobic glycolysis. In conclusion, during hypoxia, intramyocardial acidosis was caused by the increase of arterial LA level, myocardial anaerobic glycolysis and ATP breakdown, and it worsened left ventricular contractile function and relaxation. Arterial LA levels can play a major part in intramyocardial acidosis, but the increase in myocardial LA production might be beneficial to left ventricular contractile function.

Animals↗

PubMed1993

[Intra-arterial infusion chemotherapy for advanced uterine cancer before surgical treatment].

Three cases of advanced uterine cancer were treated by CDDP intra-arterial infusion chemotherapy before curative operation. In Case I (stage IVb, G2), chemotherapy was done by BOAI method before radical hysterectomy and by implantable reservoir system after operation. In Case II (IIIa, G1), modified radical hysterectomy could be performed after chemotherapy using an implantable reservoir system, though inoperable at first. In Case III (IVa, G1), the patient was given intra-uterine arterial infusion chemotherapy twice with BOAI method before radical hysterectomy. The results suggested that this treatment is effective for advanced uterine cancer, and further study of prognosis was considered necessary.

Adenocarcinoma↗

PubMed1993

[Left ventricular function during hypoxia. 1: Effect of blood glucose level].

We investigated the effects of blood glucose levels and myocardial glucose uptake on cardiac function during hypoxia in mongrel dogs (N = 50). During hypoxia (PaO2 = 20 mmHg) caused by inhalation of low concentration of oxygen for 2 hours, left ventricular (LV) function including LV pressure, maximum rate of rise of LV pressure, and cardiac index decreased significantly following initial enhancement. There were significant correlations between these hemodynamic parameters and blood glucose levels. The blood glucose levels correlated significantly with myocardial glucose uptake and blood lactic acid levels (r = 0.660: P = 0.000, r = 0.380: P = 0.000, respectively). Eight of nine dogs which died within 90 minutes during hypoxia showed low blood glucose levels and high lactic acid levels. During hypoxia, myocardial glucose uptake increased to more than five times of control value. On the other hand myocardial lactic acid uptake decreased and turned to production. At the same degree of blood lactic acid levels, LV function was maintained better with high blood glucose levels than with low levels. With low blood glucose levels, myocardial lactic acid uptake and production tended to cease. The pronounced change in LV function during hypoxia could be partially explained by decreased production of ATP due to decrease in myocardial glucose uptake and high lactic acid levels. It seems that high blood glucose levels are preferable to maintain cardiac performance under such a condition.

Animals↗

PubMed1992

[Effects of deliberate hypotension on the ischemic heart during isoflurane anesthesia--a comparison of prostaglandin E1 and sodium nitroprusside].

The effects of hypotension induced by prostaglandin E1 (PGE1) or sodium nitroprusside (SNP) on regional myocardial function and metabolism were studied in a canine heart with coronary artery stenosis. Ultrasonic dimension technique was used to assess left ventricular performance. Fourteen open-chest mongrel dogs were anesthetized with isoflurane and mean aortic pressure was maintained at approximately 80 mmHg. The left circumflex coronary artery blood flow was reduced by 40% using a screw flow regulator without affecting global and regional myocardial function. The severity of stenosis was considered almost critical. PGE1 (n = 7) or SNP (n = 7) was administered to reduce mean aortic pressure to 50 mmHg. There were no significant differences between PGE1 and SNP regarding their effect on systemic hemodynamics. Nevertheless SNP decreased percent segment shortening in the stenosed area from the pre-hypotension value more significantly than PGE1 (55.0 +/- 10.8% versus 24.2 +/- 7.3%). This suggests that regional myocardial ischemia is more deteriorated during SNP-induced hypotension. It seems that PGE1-induced hypotension is safer when it is applied to patients with coronary artery disease.

Alprostadil↗

PubMed1992

[A case of stage IVb ovarian carcinoma successfully treated with intra-arterial infusion chemotherapy using implantable reservoir system].

A patient with liver metastasis from ovarian cancer was treated by intra-arterial infusion chemotherapy (well differentiated adenocarcinoma--CDDP 50 mg/body, ADR 30 mg/body, CPA 500 mg/body (iv)). After the chemotherapy, the metastatic tumor appeared remarkably smaller and could be resected successfully at the second reduction surgery. This patient is active 30 months after the first appearance and enjoying a favorable quality of life.

Adenocarcinoma, Papillary↗

PubMed1990

[Recovery from cardiac arrest by prostaglandin E1 infusion during emergency open heart surgery].

A 21 day old infant, diagnosed as ASD, VSD, and PDA, was scheduled for an emergency radical operation. After admission, she fell into cardiac failure and was treated with artificial ventilation and infusion of inotropic agents. Anesthesia was induced with fentanyl and maintained with continuous fentanyl infusion and chlorpromazine. Dopamine and dobutamine were administered before she underwent a cor-pulmonary by-pass. At the time of release of aortic clamping, her blood pressure went down and dopamine, dobutamine and isoproterenol were administered. After completion of the cor-pulmonary by-pass, tachy-arrhythmia and hypotension occurred. Digitalis and calcium did not reverse the condition. The thorax was reopened and BP rose. After 15 min, ventricular fibrillation occurred. Defibrillation was carried out, but the heart was arrested. Even with pacing and cardiac massage, cardiac contraction did not resume. However immediately on intravenous administration of PGE1, 40 ng.kg-1.min-1, the heart started to beat. The cause of recovery from cardiac arrest was speculated to be due to reuptake of intracellular Ca2+ by PGE1. We stress therefore, that during and after cor-pulmonary by-pass procedures, PGE1 infusion may be beneficial.

Alprostadil↗

PubMed1990

[Effects of tachycardia on ischemic canine hearts during nitrous oxide-oxygen-halothane anesthesia].

Effects of tachycardia on left ventricular function, myocardial metabolism and intramyocardial pH under nitrous oxide-oxygen-halothane anesthesia, were studied in 11 canine hearts with critical coronary stenosis. A comparison was made with coronary occlusion. Critical stenosis was produced using a screw occluder to limit the left anterior descending coronary artery blood flow to prevent reactive hyperemia after 10 second occlusion. The degree of ischemia was estimated by intramyocardial pH, arterio-venous lactate and potassium. Intramyocardial pH was measured with a hydrogen ion-selective electrode implanted in the subendocardium. Tachycardia was induced by right cardiac sympathetic nerve stimulation. After 7 min tachycardia in dogs with coronary stenosis, intramyocardial pH decreased significantly from 7.09 +/- 0.10 to 6.83 +/- 0.15, then tended to return toward control levels over a period of 20 min after cessation of tachycardia, although some did not return to the control level even after 30 min. Regarding LV function, LVP and positive LV dp/dt max did not increase. Negative LV dp/dt max decreased significantly. The time constant (T) was prolonged but not significantly, while LVEDP rose considerably from 8.2 +/- 4.1 mmHg to 14.6 +/- 6.8 mmHg. In contrast, after 7 min occlusion, intramyocardial pH decreased significantly from 7.14 +/- 0.08 to 6.72 +/- 0.15 and recovered after 15 min. LVP decreased slightly. Positive and negative LV dp/dt max decreased significantly. T was not prolonged initially, but after reperfusion prolonged significantly. LVEDP increased significantly from 7.9 +/- 3.3 mmHg to 11.9 +/- 6.3 mmHg. In summary, tachycardia in dogs with coronary stenosis under nitrous oxide-oxygen-halothane anesthesia caused regional ischemia. The degree of ischemia was slightly less than with occlusion, but LV diastolic dysfunction was more prominent.

Anesthesia, Inhalation↗

PubMed1989

Effects of acute lead acetate exposure on adult guinea pigs: electrophysiological study of the inner ear.

The effects on humans of lead acetate exposure may involve the cranial nerves, since vertigo and sensory neuronal deafness have been reported in lead workers; however, there exist only a few reports concerning the dose effects of lead acetate both on the cochlea and the eighth cranial nerve. The effects of lead acetate on the cochlea and the eighth nerve were investigated systematically using cochlear microphonics (CM), whole-nerve action potential (AP), and endocochlear potential (EP) in guinea pigs (male albino Hartley). Guinea pigs were injected with 2 ml of a 1% solution of lead acetate (20 mg) once a week for 1-5 weeks. The threshold of whole-nerve AP (N1) was elevated by injection of lead acetate, even 40 mg, and whole-nerve AP (N1) output voltage decreased after injection of 100 mg of lead acetate. On the other hand, no change was observed in CM after lead acetate injection (100 mg) or in EP after lead acetate exposure (40 mg). The blood concentrations of lead acetate were as follows (mean): control, 4.5 micrograms/dl; Expt 1, 80 micrograms/dl; Expt 2, 126 micrograms/dl; Expt 3, 142 micrograms/dl. We conclude that dysfunction of the eighth nerve is induced by high-dose lead exposure, but that lead exposure does not induce electrophysiological dysfunction of the organ of Corti and the stria vascularis.

Animals↗

PubMed1989

[Microbiological and serological investigation of periodontal disease activity].

If disease activity in periodontal disease can be determined, the therapeutic measures of periodontitis may become diverse and different from patient to patient. The purpose of the present study was to evaluate the usefulness of microbiological and serological examination of periodontopathic bacteria in detecting destructive periodontal disease activity. One hundred and forty-eight sites in 52 subjects with moderate to severe periodontitis were studied clinically. Clinical parameters included plaque index, gingival index, probing depth, bleeding on probing and percent bone loss as measured radiographically. Subgingival plaque of whole sites was investigated microbiologically by means of indirect fluorescent-antibody technique with rabbit antibodies against Actinomyces viscosus, Actinobacillus actinomycetemcomitans (2 serotypes), Eikenella corrodens, Fusobacterium nucleatum, Bacteroides gingivalis and Bacteroides intermedius. The levels of serum IgG antibody to these organisms were determined by enzyme-linked immunosorbent assay with whole cell preparations. Thirty-two of 52 subjects were instructed in oral hygiene and received several sessions of scaling and root planing. The clinical, bacteriological and serological assessments were also performed after periodontal therapy. Active disease site was defined as the site of which clinical status did not be improved even after periodontal treatment. B. gingivalis, B. intermedius and A. viscosus were detected in 80% of periodontal lesions, and the proportion of B. gingivalis was the highest among six bacterial species tested. A. actinomycetemcomitans, E. corrodens and F. nucleatum were found only occasionally and in low numbers. The proportion of B. gingivalis was higher in severely inflamed sites than in clinically healthy sites. B. gingivalis and B. intermedius are rarely found in treated periodontitis sites, while the proportion of A. viscosus was slightly increased after treatment. Sera of the pre-treatment patients demonstrated significantly higher antibody levels to B. gingivalis and significantly lower levels to A. viscosus than those of healthy persons. Antibody levels reactive with other four species in the patients did not significantly differ from the levels in healthy persons. After periodontal therapy, antibody levels to B. gingivalis, B. intermedius and A. actinomycetemcomitans (serotype a) significantly decreased and the levels to A. viscosus increased to a slight degree. B. gingivalis was found more frequently in disease-active sites than in disease-inactive sites. The proportions of other bacterial species in disease-active sites did not differ from those in disease-inactive sites. The results of the present investigation suggest that monitoring B. gingivalis in subgingival plaque and serum IgG antibody titer against this organism may aid in the description and adequate treatment of the periodontal disease.

Bacteroides↗

PubMed1987