Biomedical subjects

K Suwa

Publications and source records attributed to K Suwa.

At least 55 records · Page 3Linked to original sources

PubMed1995

Which blood gas caused the brain damage?

In order to analyse the effects of various physiological parameters including blood gas data on the cerebral oxygenation, we developed a model to enable us to estimate PtO2 (tissue PO2) from these physiological parameters. This model was applied successfully to a set of blood gas data of a patient who had brain damage after cardiac surgery. Contrary to the original impression, we concluded that a very low PaCO2 of 13 mmHg towards the end of CPB was the most likely cause of his damage.

Body Temperature↗

PubMed1995

Biosynthesis of acetylenic compounds in cultured cells of Asparagus officinalis from [1-13C]- and [U-13C] Glucose.

The biosynthetic pathway of phenolics with an acetylenic group, 4-[5-(4-methoxyphenoxy)-3-penten-1-ynyl]phenol (1) and its related compounds, isolated from suspension-cultured cells of Asparagus officinalis L. (Liliaceae), was studied in feeding experiments using [1-13C]- and [U-13C] glucose. Analyses of the 13C-NMR spectra of the methyl ether and acetate of the 13C-labelled species of 1 indicated that the aromatic rings at both ends of the molecule are formed from shikimic acid. It was also assumed that the acetylenic carbons in the C5 chain could be incorporated together with its adjacent aromatic ring through any phenethyl class compound derived from phenylpropanoids, and the propenylene carbon through glycolysis metabolites with C3 carbon units.

Acetylation↗

PubMed1995

Acetylenic compounds isolated from cultured cells of Asparagus officinalis.

Three new acetylenic compounds, compounds I, II and III were isolated from the cultured cells of Asparagus officinalis L. (Liliaceae) and their structures identified as 1-methoxy-4-[5-(4-methoxyphenoxy)-3-penten-1-ynyl]-benzene, 4-[5-(4-methoxyphenoxy)-3-penten-1-ynyl]phenol and 4-[5-(4-hydroxyphenoxy)-3-penten-1-ynyl]phenol, respectively, from chemical and spectral analysis.

Acetylation↗

PubMed1995

[Anesthesia for SUMO wrestlers].

We anesthetized 34 sumo wrestlers. All patients were male. Average age was 21.1. Their height was 181.9 +/- 4.5 (mean +/- SD) cm, and they weighted 135.2 +/- 16.9 kg. Anesthetic methods used were spinal anesthesia alone in 17 patients, general anesthesia alone in 9, general anesthesia + epidural anesthesia/or spinal anesthesia/or axillary block in 8. The preoperative data showed findings common to obese patients; liver dysfunction, abnormal blood sugar, and abnormal ECG such as ST depression or left ventricular hypertrophy. For intubation, fiberscopy was required in one patient, and almost all patients required high FIO2, otherwise SaO2 decreased. For spinal anesthesia or epidural anesthesia, we needed long needles of 8 to 15 cm.

Adult↗

PubMed1995

[Statistical analysis of anesthesiologists' thinking patterns concerning regulation of the blood pressure and the concentration of inhaled anesthetics].

During surgery, the anesthesiologists adjust the concentration of inhaled anesthetics according to the change in blood pressure in order to achieve good control of anesthesia. Usually the thinking patterns of individual anesthesiologists differ from one to another. We obtained data from each anesthesiologist's thinking pattern concerning the regulation of blood pressure and the concentration of inhalational anesthesia. These patterns were analyzed statistically and compared for individual anesthesiologist. The results showed that anesthesiologists' regulation rules were formed independently of the 3 drugs and were specific to individuals. Some trends depending on institution were observed, but no statistically significant difference was found.

Anesthesia, General↗

PubMed1995

Effects of cementum-impregnated gelatine membrane on early healing following periodontal flap surgery.

The purpose of this study was to investigate the initial healing response of surgically flapped periodontal tissues in the presence of gelatine membrane compounded with particles of cementum. Four monkeys with no periodontal disease were used in this experiment. Full thickness flaps were raised and recession type defects were created on the buccal side of the maxillary lateral incisors and second premolars. Exposed root surfaces were thoroughly curetted, and composite cementum-impregnated membranes placed directly onto planed root surfaces. Flaps were then sutured back to the original position. Animals were sacrificed at 2, 4, 7 and 10 post-surgical days, and block specimens including the tooth, gingiva and bone were subsequently processed for light and electron microscopy. The resultant analysis revealed that gelatine membranes were partially resorbed at 2 days post-surgery and completely resorbed by 10 postoperative days. In the early stages of gelatine resorption, most liberated cementum particles accumulated on planed dentin surface but some became demineralized within the surgical wound. Cementoblast-like cells with well-developed rough endoplasmic reticulum appeared on the root surface 7 days following surgery. Newly synthesized collagen fibrils aligned parallel to the root surface were seen at 10 post-surgical days. The results suggest that the newly developed composite membrane enhances the formation of new periodontal attachment.

Animals↗

PubMed1995

[Analysis of the anesthesiologists' action patterns concerning regulation of the blood pressure and the concentration of inhalational anesthesia].

The action pattern of each anesthesiologist is different. We have developed a computer program simulating anesthesiologists' action patterns during operation and have extracted the action patterns of anesthesiologists using a computer program. The simulation program was designed to gather data on anesthesiologists' response to the change in blood pressure. The results indicate that the action pattern differs significantly from one anesthesiologist to another in responding to the change in blood pressure. That of one particular anesthesiologist remained the same, regardless of the agent used. His action pattern is directed only by the value of MAC and according to his own personal principle.

Anesthesia, Inhalation↗

PubMed1994

Respiratory muscle pressure analysis in pressure-support ventilation.

The extent to which respiratory muscles are exerted during partially supported ventilation is difficult to differentiate, because these muscles and the ventilator work simultaneously to produce ventilation. We have developed a new method for determining the pressure developed by the respiratory muscles in partially supported ventilation. In seven patients on pressure-support ventilation (PSV), pressure, flow, and lung volume change were measured at the airway opening. Various PSV levels (0-15 cmH2O) were applied to each patient in random order. By utilizing a model of respiratory mechanics, we calculated the pressure developed by the respiratory muscles and the inspiratory work performed by the muscles from the measured parameters by use of the resistance and elastance of the respiratory system obtained during controlled ventilation. Increasing PSV from 0 to 15 cmH2O modulated the resultant breathing pattern, i.e., increasing tidal volume and decreasing respiratory rate. The respiratory muscle pressure, although less negative, had a shape that corresponded to the shape of airway occlusion pressure at each PSV level, and both pressures decreased concomitantly with increasing PSV. The respiratory muscle work progressively decreased with increasing PSV. This analysis enabled clear and continuous quantifications of the respiratory muscle force generation and inspiratory work during partially supported ventilation.

Adult↗

PubMed1994

[Single dose toxicity studies of lactitol (NS-4) in mice and rats].

The single dose toxicity studies of lactitol, a hepatic encephalopathy drug, were performed in ddY mice and SD rats of both sexes by administering the drug orally, intravenously or subcutaneously. The drug was administered as a single dose followed by a 14-day observation. Oral LD50 values of lactitol were estimated to be between 23 and 30 g/kg in male mice, approximately 30 g/kg in female mice, and more than 30 g/kg in male and female rats. Lethal dose was more than 10 g/kg intravenously and subcutaneously in mice and rats of both sexes. The signs of toxicity in mice and rats observed following the administration of this drug included the following: decreased spontaneous movement [p.o., i.v., s.c.]; diarrhea, oligopnea or prone position, transient decreased body weight [p.o]. There were no treatment-related changes in gross examination. Based on these results, it was found that lactitol had a very low acute toxicity when administered by a single dose method in mice and rats.

Administration, Oral↗

PubMed1994

[Two cases of unexplained pupillary dysfunction after cardiac surgery in severely diabetic patients].

We experienced two cases of unexplained pupillary dysfunction in severely diabetic patients after cardiac surgery. In both patients, marked bilateral dilatation of the pupils and the absence of light reflex were recognized immediately after leaving the operating room. The pupillary dysfunction, however, was not accompanied by other neurological deficits, and the pupil sizes returned normal spontaneously by 24 hours. We speculated that impaired peripheral perfusion during cardiopulmonary bypass caused transient tissue ischemia on the basis of microangiopathies of severe diabetes mellitus. Bilateral ciliary ganglia were thought to be most susceptible to the impaired perfusion and responsible for the pupillary dysfunction.

Anesthesia↗

PubMed1994

[The effects of incentive spirometry on pulmonary functions].

The effects of incentive spirometry on pulmonary functions were studied in 46 normal adults of advanced age ('N' group) and 42 patients with chronic pulmonary emphysema ('E' group). Subjects of the both groups carried out deep breathing exercises by using incentive spirometry, 'Souffle', for five minutes, five times daily for four weeks. Pulmonary functions and arterial blood gases were measured at the start of exercise program, and at two and four weeks after the start. Both groups showed significant increases in VC, FEV1.0, peak expiratory flow, the flow at 75 percent VC (V75), maximal voluntary ventilation and PaO2, and a significant decrease in A-aDO2 at both two and four weeks after the start. In addition, V25 increased significantly in 'E' group. It is concluded that 'Souffle' is one of the useful preoperative respiratory managements for elderly patients and those with chronic pulmonary emphysema.

Aged↗

PubMed1993

Natural frequency/damping coefficient relationship of the catheter-manometer system required for high-fidelity measurement of the pulmonary arterial pressure.

Using a digital simulation method, we analyzed the relationship between natural frequency (fn) and damping coefficient (Zeta) of the catheter-manometer system required for high-fidelity measurement of the pulmonary arterial pressure. The pulmonary artery pressure waveform was obtained with a catheter-tip transducer and it was fed into a dynamic simulator programmed on a computer. The original waveform and the output of the simulator were compared and judged visually for the fidelity. From this analysis, the combination of fn and Zeta was obtained and was plotted on a fn-Zeta diagram. It showed as an area, which was convex on the left side and open on the right side. The left-convex endpoint was located at a damping coefficient of about 0.7. At a lower heart rate, this area was extended to the lower frequency side, while, at a higher heart rate, this area was limited to the higher frequency side. The fn-Zeta diagram was also constructed theoretically by calculating the relations between natural frequencies and damping coefficients of a second order system with the amplitude and phase error tolerance set at +/-5% respectively.

Journal Article↗

PubMed1993

Pulmonary capillary pressure measured with a pulmonary arterial double port catheter in surgical patients.

We developed a pulmonary artery (PA) double port catheter technique for reliable clinical measurements of pulmonary capillary pressure (Ppc). In seven elective surgical patients, the PA double port catheter with the second PA port 1 cm proximal to the balloon was inserted. The two PA ports, connected to identical pressure measuring systems, provided the pulmonary arterial pressures (Ppa) distal and proximal to the balloon. After general anesthesia was stabilized, the two Ppas were measured simultaneously during a PA occlusion maneuver during 10 s of apnea. The instant of occlusion was determined precisely as the time when the two Ppa traces sharply diverged. A single exponential equation was fitted to the segment of distal Ppa tracing starting 0.3 s after the instant of occlusion. Ppc was determined as the value of the exponential fit extrapolated to time 0. In six of seven patients, PA occlusion occurred consistently in the early systolic phase regardless of the timing of balloon inflation. Mean Ppa, Ppc, and pulmonary arterial wedge pressure were 16.6, 11.8, and 7.6 torr. The ratio of venous to total resistance ranged from 0.37 to 0.54 (mean:0.46). We conclude that this technique is clinically feasible and valuable in precise definition of the instant of PA occlusion. By defining PA occlusion consistently, this technique can provide reliable Ppc estimation in the clinical settings.

Catheterization, Swan-Ganz↗

PubMed1993

Cardiac autonomic dysfunction in rotogravure printers exposed to toluene in relation to peripheral nerve conduction.

The autonomic nervous effects of toluene remain less clear. To clarify this neurotoxicity, ten rotogravure printers and the same number of age-matched unexposed controls were examined, by using the coefficient of variation in electrocardiographic R-R intervals (CVRR), the distribution of nerve conduction velocities (DCV) and the maximal motor and sensory nerve conduction velocities (MCV and SCV) in the median nerve. Also, the C-CVHF and C-CVLF (two component CVs of the CVRR reflecting parasympathetic and sympathetic activities, respectively) were computed from component spectral powers using autoregressive spectral and component analyses. These printers had been exposed to toluene (estimated exposure levels of toluene at 83 ppm) for 1-36 years. The CVRR and C-CVHF were significantly lower in the printers than in the controls. No significant difference between the printers and the controls was found in either any DCV parameters or the SCV in the forearm, except the MCV and the SCV in the palm. In the light of previous work on the brainstem/hippocampus damages due to toluene, these data suggest that toluene causes potential damages in the central autonomic nervous system, mainly parasympathetic hypoactivity.

Adult↗

PubMed1993

[A graphic presentation of the anesthesiologist's action pattern].

The action patterns of anesthesiologists are different among individuals. We have developed a graphic presentation system for anesthesiologists' action patterns using computer graphics. The resulting representation is called "thought map". Data were obtained from 6 anesthesiologists (4 certified instructors and 2 new doctors) with a time interval of 2 years, regarding the use of 3 drugs (enflurane, sevoflurane and isoflurane). The "maps" were compared among individuals, dates and drugs. The following results were obtained: 1) significant differences existed among individuals, 2) during the 2-year time interval, 2 new drugs were introduced and the practice pattern alterations were seen in the maps, 3) for the 2 new anesthesiologists, the maps show the process of professional knowledge acquisition. We propose an index ("immovable rate"), denoting the proportion of the map where concentration of the drug didn't change. This index is to be used for evaluating human thinking.

Anesthesia, Inhalation↗

PubMed1992

Analysis of oxygen transport and oxygen utilization combined.

We propose a model which combines oxygen transport system from blood to tissue with oxygen utilization system at the tissue. The model consists of 3 equations; the relationship between tissue P(O)(2) (Pts(O)(2)) and O(2) utilization (Vrc(O)(2)), diffusion from vessel to tissue, and Fick equation. This model has two advantages. First, it is self-consistent. Varying Vrc(O)(2) varies the oxygen transport. Second, it enables to analyze the effects of various factors of oxygen transport/utilization on other factors. We applied this model to the brain tissue. Following values were assumed. Critical tissue P(O)(2) (Pcrit(O)(2)) 2 mmHg; oxygen utilization above this level 3 ml.min(-1).100 g(-1); diffusion coefficient from blood vessel to tissue (D) 0.2 ml.min(-1).mmHg(-1).100 g(-1); cerebral blood flow (CBF) 50 ml.min(-1).100 g(-1); hemoglobin 15 g.100 ml(-1). Hill equation was used for oxygen dissociation curve with n of 2.7 and P50 of 27.0 mmHg. From these, the following values were obtained; Pv(O)(2), Pts(O)(2) and Vrc(O)(2). The changes were analyzed for the 5 input values, Pa(O)(2), CBF, D, P50 and Hb, changing from zero to their respective normal values. A reduction of a single parameter down to 50% of normal barely affected oxygen utilization. A further reduction resulted in significant oxygen utilization. Under conditions studied, a decrease in P50 reduced oxygen utilization faster than that in any other parameters.

Journal Article↗

PubMed1992

Programming a predictive formula for angina and other risk factors in patients with cardiac diseases undergoing noncardiac operations.

We programmed a formula which predicts the incidence of either myocardial infarction or cardiac death during the postoperative period. The original formula was proposed by Shah et al, based on their own data and analysis. The program is simple and is written in a language called Quick Basic. The use of this program is also simple. Such a program has improved the use of this analysis substantially. The program has been posted on to a few Computer network services as a free software.

Journal Article↗

PubMed1992

Analysis of oxygen transport to the brain when two or more parameters are affected simultaneously.

We composed a model, combining oxygen transport system from blood to tissue with the oxygen consumption system at the tissue. The aim of this study is to apply it to the brain tissue under conditions when two or more oxygen transport parameters are affected simultaneously. The following values were assumed. Critical tissue P(O)(2) (Pcrit(O)(2)) 2 mmHg; oxygen consumption above this level 3 ml.min(-1).100 g(-1); diffusion coefficient from blood vessel to tissue (Dvt) 0.2 ml.min(-1).mmHg(-1).100 g(-1); cerebral bloow flow (CBF) 50 ml.min(-1).100 g(-1); hemoglobin 15 g.100 ml(-1). The Hill equation was used for oxygen dissociation curve with n of 2.7 and P(50) of 27.0 mmHg. The changes of oxygen consumption of the brain (V(O)(2)) were analyzed when 2 or more of 5 parameters, Pa(O)(2), CBF, Dvt, P(50) and hemoglobin decreased simultaneously from their respective normal values. As the number of parameters affected increased, the level at which oxygen consumption begins to be affected became higher. With all five parameters combined, a reduction down to 78 per cent of normal resulted in tissue hypoxia. We conclude that the oxygen consumption of the brain is fairly resistant when only one parameter is affected, but it becomes increasingly vulnerable when several parameters are affected simultaneously. A clinically important finding is that the brain is particularly vulnerable to a combination of hypocapnia and a decreased level of 2,3DPG.

Journal Article↗