Search PubMed⌕ Search

Biomedical subjects

K Ueyama

Publications and source records attributed to K Ueyama.

At least 73 records · Page 4Linked to original sources
PubMed1996

Rewarming: comparison of contemporary heat-exchangers.

Heat exchange methods must be efficient in order to minimize the patient's pump time. However, comparisons of heat exchangers have been rare. Therefore, the in vivo functions of the most popular, currently available heat exchangers, Sarns, Cobe, Medtronics Maxima, and an experimental model manufactured by Haemonetics were compared. Thirty-two pigs weighing between 63-74 kg were placed on cardiopulmonary bypass with right atrial and ascending aorta cannulation through a right thoracotomy. Thermocouples were placed in the pump tubing before and after the heat exchangers, in the water line before and after the heat exchangers, in the inlet and outlet line of the pump, and the esophagus, brain, bladder, rectum, liver, myocardium, and tympanic membranes of the pigs. They were cooled until the bladder temperature was reduced to 14 degrees C, and maintained at that temperature for 10 minutes. Rewarming was begun until the bladder temperature became 37 degrees C. The pump flow was maintained between 50-60 ml/kg/min with standard ventilation. Cobe, Sarns, Maxima, and Haemonetics heat exchangers were tested and their function determined by comparing the time necessary for rewarming. The Haemonetics heat exchanger required a significant shorter time than the others to rewarm the pigs to normal bladder temperature (Cobe 82.0 +/- 12.0, Sarns 80.3 +/- 15.4, Maxima 89.0 +/- 13.9 Haemonetics 68.7 +/- 13.4, p < 0.05). The principal advantage was seen at the lowest temperatures between the Haemonetics experimental heat exchanger and the other heat exchangers. No statistically significant superiority was seen at higher temperatures. The current heat exchangers are relatively comparable but improved performance is possible with available technology.

Animals↗
PubMed1995

Proton magnetic resonance spectroscopy of the left medial temporal and frontal lobes in chronic schizophrenia: preliminary report.

Proton magnetic resonance spectroscopy (MRS) was performed in 30 medicated schizophrenic patients and 30 normal subjects. Two groups, each containing 15 schizophrenic patients and 15 age-and sex-matched normal subjects, received MRS examinations for different volumes of interest, either the frontal lobe or the medial temporal lobe. Schizophrenic patients showed a decrease in the ratios of N-acetylaspartate (NAA)/choline-containing compounds (Cho) and NAA/creatine-phosphocreatine (Cr). The patients also showed an increase in the ratio of Cho/Cr in the left medial temporal lobe but not in the left frontal lobe. The age at onset of illness correlated positively with the ratios of NAA/Cho and NAA/Cr in the medial temporal lobe. No significant correlation was observed between the ratios of NAA/Cho, NAA/Cr, or Cho/Cr in the left medial temporal and frontal lobes and clinical symptomatology as assessed by the Scale for the Assessment of Negative Symptoms and the Positive and Negative Syndrome Scale.

Adult↗
PubMed1995

Pressure characteristics in arterial grafts for coronary bypass surgery.

The haemodynamic properties of arterial grafts were studied by measuring the pressure waveform at the tip of the grafts in 28 patients who underwent coronary artery bypass surgery (CABG). The internal thoracic and gastroepiploic arteries were harvested as pedicles for CABG. Pressure wave of the ascending aorta and arterial grafts were simultaneously recorded with an electrocardiogram under stable haemodynamic conditions before cardiopulmonary bypass. Systolic, diastolic and mean pressures were measured, and mean systolic and diastolic pressures calculated for systolic and diastolic areas divided by time. The ascending aorta showed high sustained diastolic pressure that decreased gradually. Pressures in the internal thoracic and gastroepiploic artery grafts had narrow contours and decreased rapidly. Pressure waveforms in the internal thoracic and gastroepiploic artery grafts had a notch between the systolic and diastolic contours. There was no difference in systolic pressure between the ascending aorta and internal thoracic and gastroepiploic artery grafts. Diastolic pressures were 64(9), 55(7), and 51(6) mmHg in the ascending aorta and internal thoracic and gastroepiploic artery, respectively. Mean(s.d.) pressures were 75(9), 65(9) and 59(7) mmHg in the ascending aorta and internal thoracic and gastroepiploic artery grafts, respectively. Diastolic and mean pressures in the internal thoracic artery grafts were significantly lower than in the ascending aorta but significantly higher than in the gastroepiploic artery grafts. The mean(s.d.) calculated diastolic pressure in the internal thoracic artery grafts was significantly lower than in the ascending aorta but significantly higher than in the gastroepiploic artery grafts. The inferior capacity of flow through the arterial grafts may be mainly attributable to reduced diastolic pressure, which is caused by anatomical characteristics.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Shortening of the hippocampal formation in first-episode schizophrenic patients.

Shortening of hippocampal formation (HF) in chronic schizophrenic patients have been demonstrated in our previous study. The purpose of the present study is to test if shortening of the HF occurs in schizophrenic patients suffering their initial psychotic episode. We performed contiguous, 1 mm thick, magnetic resonance imaging scans in 20 first-episode schizophrenic patients, 21 chronic schizophrenic patients, and 25 healthy subjects. Both groups of schizophrenic patients demonstrated significant shortening of the HF compared with normal controls (first-episode schizophrenia, 5.3%; chronic schizophrenia, 8.0%). However, the HF length was not significantly different between the first-episode and chronic schizophrenic patients. No significant correlation was seen between the HF length and the duration of illness in chronic schizophrenic patients. These results suggest that the HF shortening observed in schizophrenic patients may be genetic and/or developmental in origin.

Acute Disease↗
PubMed1995

[Composite arterial conduits with internal thoracic artery and inferior epigastric artery for a myocardial revascularization].

From November 1992 to February 1995, 10 patients were submitted to myocardial revascularization using composite arterial conduit with internal thoracic artery (ITA) and inferior epigastric artery (IEA). The age ranged from 48 to 68 years (mean age, 60.3 years); all patients were male. All patients had double-or triple vessel disease. The mean ejection fraction was 61.8% (range, 43 to 77%). We used 28 arterial conduits including 5 right ITAs, 10 left ITAs, 10 IEAs, and 3 right gastroepiploic artery. 10 IEAs were anastomosed to one ITAs and 10 composite arterial conduits were constructed (branched in 3, lengthened in 7). In 5 patients a double ITAs were used in a single patient. There was no operative mortality and fetal complication. Early postoperative angiographic controls demonstrated 100% patency of composite grafts in 9 of 10 patients. The composite arterial graft using ITAs and IEAs is feasible and the anastomoses so performed are completely safe.

Aged↗
PubMed1994

Magnetic resonance imaging and brain-stem auditory evoked potentials in neuro-Behçet's disease.

We studied central nervous system lesions in patients with neuro-Behcet's disease using magnetic resonance imaging (MRI) of the brain and recording of brain-stem auditory evoked potentials (BAEPs). MRI revealed abnormal findings in seven of eight patients. MRI studies demonstrated extensive regions with high intensity signal in the brain stem and/or basal ganglia on T2-weighted images obtained during the acute stage of the disease in three patients. One of these patients had a strongly gadolinum-enhanced round lesion in the lower pons. In four of the other five patients with chronic disease, brain-stem atrophy was observed on T1-weighted images. Atrophic changes were more severe in the brain stem than in the cerebellum. Abnormal BAEPs were observed in three patients and consisted of prolongation of interpeak latency of waves III-V and defects of wave III or V. Abnormal BAEPs were recorded in patients with severe inflammatory changes or progression of atrophic changes in the brain stem. Our findings show that MRI and BAEPs are useful in detecting the presence and assessing the degree of neurological involvement in patients with neuro-Behçet's disease.

Adult↗
PubMed1994

31P magnetic resonance spectroscopy of the medial temporal lobe of schizophrenic patients with neuroleptic-resistant marked positive symptoms.

31P magnetic resonance spectroscopy was performed in 16 mediated schizophrenic patients with neuroleptic-resistant marked positive symptoms and in 16 healthy volunteers matched for age and sex in order to determine what changes in phosphorus metabolites are detected in such patients as compared to the controls. The schizophrenic patients showed an increased level of phosphodiesters in the bilateral medial temporal lobes. They also showed a decrease in the level of beta-ATP in the left medial temporal lobe. These findings suggest that schizophrenic patients with prominent positive symptoms refractory to neuroleptics may have a disturbance of bilateral membrane phospholipid and left-sided high-energy phosphate metabolism in the medial temporal lobe.

Adolescent↗
PubMed1994

Correlation of third ventricular enlargement and EEG slow wave activity in schizophrenic patients.

Twenty-eight schizophrenic patients and 22 normal control subjects underwent magnetic resonance imaging (MRI) and topographic electroencephalography (EEG) in a study attempting to correlate morphological and electrophysiological findings. Schizophrenic patients had larger anterior horns of the lateral ventricles and third ventricles than normal control subjects. Schizophrenic patients showed more delta wave activity in the right parietooccipital region than normal control subjects. Alpha 2 wave activity was reduced in the entire region in schizophrenic patients. In schizophrenic patients, a significant positive correlation was seen between the area of the third ventricle and delta wave activity in the right occipital region. These results suggest that schizophrenic patients may have a dysfunction of diencephalic structures associated with morphological abnormality.

Adult↗
PubMed1994

Developing of EEG print and its preliminary technical application.

In this report, we discuss a method called "EEG print" to represent EEG contrast mapping in time and frequency domains simultaneously. A bank of bandpass FIR (Finite Impulse Response) digital filters is used to obtain EEG prints. EEG prints were taken from four areas (F3, F4, O1 and O2) of EEG when healthy subjects were at rest with their eyes closed. The pattern of the prints was classified into four types: alpha type, beta type, alpha + beta type and complex type. It was found that EEG prints may vary from person-to-person but they usually do not vary much between the four areas for a given person. The method is further modified to obtain "differential EEG prints" to investigate whether meaningful higher frequency EEG components exist. Differentiation of EEG resulted in marked intensification of the fast waves, using 0.14 Hz as the critical point. In differential EEG print with higher order differentiation, amplification in the high frequency components increase their frequency. As a result, it is possible to observe variations in the high frequency components, which are otherwise not detectable in the usual EEG print. EEG print can be used for representing the function of the brain. Using the method for classification of EEG print patterns, described in this paper, we can clarify not only the characteristics of the normal brain but also the pathophysiology of mentally-ill patients.

Alpha Rhythm↗
PubMed1994

Intracranial self-stimulation and locomotor traces as indicators for evaluating and developing antipsychotic drugs.

When chlorpromazine (CPZ) and lithium chloride (LiCl) are compared, the former suppresses both rat's intracranial self-stimulation (ICSS) and methamphetamine (MAP)-induced hyperactivity. On the other hand, the latter suppresses only MAP-induced abnormal hyperactivity but hardly suppresses a purpose-oriented ICSS associated with the reward system. Therefore, LiCl inhibits abnormal hyperactivity induced by MAP, but it does not suppress physiological motivation. Using the two types of antipsychotic drugs, the authors propose a method of combining the ICSS and locomotor activity together with its traces. These proposals are useful indicators for evaluating and developing the new antipsychotic drugs which are used clinically for psychotic patients and for understanding the drug-induced akinesia and anhedonia.

Animals↗
PubMed1994

[A case report of coronary artery bypass grafting surgery with aprotinin in a patient undergoing chronic haemodialysis].

A 61-year-old patient who was receiving haemodialysis because of chronic renal failure developed unstable angina pectoris with three vessel disease. We performed successful coronary artery bypass grafting, using aprotinin to reduce blood loss. Blood loss during the operation was 750 ml, and during a 6 hour period after the operation it was 150 ml. This amount seemed to be small. No adverse clinical effects attributable to aprotinin were seen, and urine volume and plasma creatinine were not different before and after the operation. In summary, aprotinin is useful adjunct to open heart surgery in chronic haemodialysis patients.

Aprotinin↗
PubMed1994

[Central nervous disease and manic state].

We often observe several psychotic symptoms in physical illness-delusions, hallucinations, manic-depressive state and nervous state, for example. The purpose of this chapter is to account for the relationship between manic-depressive state and central nervous disease. Secondary mania is considered to occur in association with physical illness. The criteria for a diagnosis of it is a duration of at least one week, elated or irritable mood, and at least two of the following: hyperactivity, "push of speech", flight of ideas, gradiosity, decreased sleep, distractibility, and lack of judgement. Depressive state is often observed in infarction, infection, neoplasm, head injury and degenerative disease. The differential diagnosis of pseudodementia and pseudodepression are receiving increased attention, we showed the table of clinical characteristics for distinguishing pseudo-depression from pseudodementia.

Cerebrovascular Disorders↗
PubMed1994

[Study of pulmonary function after CABG with pleurotomy].

We studied the influence of pleurotomy during harvesting IMA for CABG on postoperative pulmonary function. Ninety nine cases underwent CABG surgery from January 1991 to July 1992, were divided into three subgroups, 45 patients (subgroup AY 2) having bilateral IMAs graft with pleurotomy, 45 patients (subgroup AY 1) having unilateral IMA graft with pleurotomy, 9 patients (subgroup AN) having unilateral IMA graft or vein grafts without pleurotomy. Frequencies of chest X-rays abnormality such as elevation of diaphragm and accumulation of pleural effusion before discharge around 2 weeks after surgery, were not significantly different among three subgroups. 58 cases without chest X-rays abnormalities were divided into three subgroups in the same way. There was no case with late extubation or with postoperative pulmonary complication. At first we compared pre-with postoperative pulmonary function in each subgroups. Pulmonary function (VC, FEV1.0, peak flow, MMF, V50, V25) was significantly deteriorated in the patients with pleurotomy, while VC, FEV1.0, peak flow significantly decreased, and MMF, V50 and V25 tended to decrease in the patients without pleurotomy. Moreover, magnitude of change of pulmonary function from pre- to postoperative period were not different significantly among three subgroups. In conclusions pleurotomy itself didn't appear to influence postoperative morbidity.

Coronary Artery Bypass↗
PubMed1994

[The management of mediastinitis after cardiac surgery].

Of 1067 consecutive patients who underwent cardiac surgery from 1985 to 1992, 19 (1.7%) patients experienced sternal wound complications. All patients required operative intervention with positive bacterial cultures. Before 1990, a group of 13 patients were treated by continuous closed irrigation with dilute povidone-iodine solution. Four patients died (30%). In another group of 6 patients who received omental or pectral muscle flap transfer after 1990, 2 patients died (33%). The mean duration of hospitalization for mediastinitis was 63 days in this group, which was significantly shorter than that of the former group (105 days). From these experiences, we conclude that omental or pectral muscle transfer is an excellent method of management for mediastinitis after cardiac surgery, and is better than continuous closed irrigation method.

Adult↗
PubMed1994

[Comparison of long-term clinical results and cost-effectiveness of percutaneous coronary angioplasty and coronary artery bypass grafting].

Cost-effectiveness was studied in 313 cases who had PTCA and 161 cases who had CABG as a first measure of interventional therapy for their coronary heart disease. Follow-up time ranged from 2 years to 5 years and 9 months with a mean interval of 3 years and 10 months. In the PTCA group a mean of 1.33 successfully dilated vessels/patient was obtained, but a total of 100 additional PTCA or bypass surgery procedure was necessary in the follow-up period. In the CABG group a mean of 2.60 patent grafts/patient was obtained. Mean length of hospital stay and charge was 21.9 days and 2,071 thousand yen in the PTCA group, and 82.2 days and 5,122 thousand yen in the CABG group through the entire follow up period. Cardiac event-free survival rate was significantly worse in the PTCA group. In the subgroup of two vessel disease, mean number of successfully dilated targets or patent grafts was 1.32 in the PTCA group and 1.88 in the CABG group. Total length of hospital stay and charge was 24.1 days and 2,352 thousand yen in the PTCA group and 86.2 days and 4,903 thousand yen in the CABG group. Cardiac event-free survival rate was significantly worse in the PTCA group. In the subgroup of three vessel disease, PTCA yielded 1.34 dilated target vessels, whereas CABG 2.66 patent grafts, which was two times more than the former one. Total length of hospital stay and charge was 32.7 days and 2,612 thousand yen in the PTCA group, and 82.4 days and 5,225 thousand yen in the CABG group.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Effect of low-dose aprotinin on coagulation and fibrinolysis in cardiopulmonary bypass.

To study the effect of low-dose aprotinin on hemostasis in patients undergoing cardiopulmonary bypass (CPB) for coronary artery bypass operations and to elucidate the mechanism of aprotinin action, we randomized 14 of 27 patients to receive 30,000 KIU/kg aprotinin in the CPB priming volume and 7,500 KIU/kg aprotinin intravenously each hour during CPB (1 patient was excluded from the aprotinin group because of protamine shock). Intraoperative and postoperative blood loss was significantly reduced in the aprotinin group. Antithrombin III level was significantly decreased, and the levels of thrombin-antithrombin III complexes were significantly increased during CPB in both groups, indicating activation of the clotting system. The marked increase in fibrin(ogen) degradation products during CPB in the control group, indicating enhanced fibrinolytic activity, was significantly reduced in the aprotinin group. alpha 2-Plasmin inhibitor was significantly reduced during CPB in the control group. The marked increase in alpha 2-plasmin inhibitor-plasmin complexes in the control group, indicating plasmin activity, was significantly reduced in the aprotinin group. A marked decrease in the platelet count was observed during CPB similarly in both groups. These findings demonstrated that low-dose aprotinin administration was effective in reducing intraoperative and postoperative blood loss and that activation of the clotting system during CPB was not followed by hyperfibrinolysis in aprotinin-treated patients. The improved hemostasis is mainly attributable to the prevention of hyperfibrinolysis during CPB.

Antifibrinolytic Agents↗