Biomedical subjects

A Ohtaki

Publications and source records attributed to A Ohtaki.

At least 19 recordsLinked to original sources

PubMed2006

[Surgical fixation of the ribs for flail chest injuries].

The record of 20 patients presenting with flail chest injury from 1998 to 2005 was reviewed to determine surgical indication and timing. There were 4 groups with each indication as followed: 1) 8 patients with surgical indication for injury regions other than fractured ribs, 2) 5 without improvement of flail chest after internal pneumatic stabilization for more than 10 days, 3) 4 performed surgical fixation positively for flail chest with respiratory failure, 4) 3 with strong deformation of the thorax without respiratory failure. Eight patients (40%) required artificial respiration for more than 6 days after surgical stabilization. The reasons of prolonged artificial respiration included unconsciousness in 4 patients, pneumonia in 2, and others in 2. In the group consisting of 8 patients taking more than 6 days to be extubated after surgical fixation, the injury severity score (ISS) was significantly higher (p = 0.006) than that of the other group. In patients with no improvement of flail chest after internal pneumatic stabilization for more than 10 days, surgical fixation reduces the period of internal pneumatic stabilization and the risk of pneumonia. For the elderly who can develop complications easily, early indication of surgical fixation should be considered. In patients with unconsciousness or ISS > or = 25, the extubation delays frequently after surgical fixations.

Adult↗

PubMed2002

Lung impairment following cardiac surgery in patients with pulmonary hypertension.

BACKGROUND: Postoperative respiratory management following cardiac surgery is sometimes troublesome in patients with pulmonary hypertension. We retrospectively studied the relationship between the etiology of preoperative pulmonary hypertension and the postoperative decline of blood oxygenation capacity by focusing on the postoperative intravascular fluid volume. METHODS: Sixteen adult patients with an atrial septal defect (preload group) and 17 patients with solitary mitral valve disease (afterload group) were studied. The mean age of the patients in the preload and afterload group was 51 and 52 years old, respectively. RESULTS: Preoperative pulmonary-systemic pressure ratio and pulmonary artery resistance index were significantly higher in the preload group than in the afterload group. The respiratory index (RI) and the pulmonary shunt ratio (Qs/Qt) measured immediately after the operation was larger in the afterload group than in the preload group. Postoperative RI and Qs/Qt remained high until postoperative day 3 in both groups. In the preload group RI on postoperative day 1 had a reverse correlation with the central venous pressure (CVP). Meanwhile, the RI in the afterload group on postoperative day 1 was slightly larger in patients with a high CVP and pulmonary capillary wedged pressure. Similar relationships were seen in the relations between pulmonary capillary wedged pressure and RI in the afterload group. CONCLUSIONS In conclusion, a preoperative pulmonary vascular change and a postoperative precipitous decrease of pulmonary blood flow may have caused postoperative lung oxygenation impairment in the preload group. An extended period of extracorporeal circulation associated with cardiac arrest and postoperative volume overload may have caused lung impairment in the afterload group. In aspect of postoperative management, low CVP is beneficial to the patients in the afterload group, however, hypovolemia should be avoided in patients of the preload group.

Blood Gas Analysis↗

PubMed2002

Peripheral pulmonary atelectasis and oxygentation impairment following coronary artery bypass grafting.

BACKGROUND: Severe pulmonary oxygenation impairment occurred in some patients with pleurotomy during the harvest of the internal mammary artery graft followed by coronary artery bypass grafting (CABG). Peripheral pulmonary atelectasis in the postoperative chest X-ray was detected in these patients. We studied the efficacy of intraoperative positive end-expiratory airway pressure (PEEP) therapy for the prevention of postoperative pulmonary oxygenation impairment. METHODS: The pleural cavity was intraoperatively opened in 40 patients with solitary CABG procedure performed during 5 years since January 1992. These patients were divided into two groups. Intraoperative PEEP therapy, which is initiated just after pleurotomy, was not used in 32 patients before May, 1996 (control group) and used for recent 8 patients with pleurotomy (PEEP group). The mean age of patients was 60 years old in the control group and 68 in the PEEP group. RESULTS: Respiratory insufficiency (A-aDO2 >400 mmHg and RI >1.5) was detected in 6 patients in the control group. Three out of these 6 patients required long-term mechanical respiratory support over a week. No respiratory insufficiency occurred in patients of the PEEP group. Values of PaO2, A-aDO2, respiratory index and shunt ratio were significantly worse in the control group than in the PEEP group. CONCLUSIONS: In conclusion, PEEP therapy may prevent pulmonary atelectasis and oxygen impairment after CABG.

Aged↗

PubMed2001

Role of Phe286 in the recognition mechanism of cyclomaltooligosaccharides (cyclodextrins) by Thermoactinomyces vulgaris R-47 alpha-amylase 2 (TVAII). X-ray structures of the mutant TVAIIs, F286A and F286Y, and kinetic analyses of the Phe286-replaced mutant TVAIIs.

Phe286 located in the center of the active site of alpha-amylase 2 from Thermoactinomyces vulgaris R-47 (TVAII) plays an important role in the substrate recognition for cyclomaltooligosaccharides (cyclodextrins). The X-ray structures of mutant TVAIIs with the replacement of Phe286 by Ala (F286A) and Tyr (F286Y) were determined at 3.2 A resolution. Their structures have no significant differences from that of the wild-type enzyme. The kinetic analyses of Phe286-replaced variants showed that the variants with non-aromatic residues, Ala (F286A) and Leu (F286L), have lower enzymatic activities than those with aromatic residues, Tyr (F286Y) and Trp (F286W), and the replacement of Phe286 affects enzymatic activities for CDs more than those for starch.

Alanine↗

PubMed2001

Studies on the hydrolyzing mechanism for cyclodextrins of Thermoactinomyces vulgaris R-47 alpha-amylase 2 (TVAII). X-ray structure of the mutant E354A complexed with beta-cyclodextrin, and kinetic analyses on cyclodextrins.

Crystals of the mutant E354A of Thermoactinomyces vulgaris R-47 alpha-amylase 2 (TVAII) complexed with beta-cyclodextrin were prepared by a soaking method, and the diffraction data were collected at 100 K, using Synchrotron radiation (SPring-8). The crystals belong to an orthorhombic system with the space group P2(1)2(1)2(1) and cell dimensions a = 111.1 A, b = 117.7 A, c = 113.3 A, which is almost isomorphous with crystals of the wild-type TVAII, and the structure was refined to an R-factor = 0.208 (R(free) = 0.252) using 3.0 A resolution data. The refined structure shows that the interactions between Phe286 and two C6 atoms of beta-cyclodextrin at the hydrolyzing site are important for TVAII to recognize cyclodextrins as substrates. This observation from the X-ray structure was supported by kinetic analyses of cyclodextrins using the wild-type TVAII, the mutant F286A and F286L. These studies also suggested that the TVAII-hydrolyzing mechanism for cyclodextrins is slightly different from that for starch.

Amino Acid Substitution↗

PubMed2001

Effect of bulking agent on the reduction of NH3 emissions during thermophilic composting of night-soil sludge.

Night-soil sludge contains a high percentage of nitrogen and releases large amounts of ammonia when it is composted. In this research, three types of bulking agents, sawdust, perlite, and activated carbon, were used, and the effects of these bulking agents on the reduction of NH3 emissions during thermophilic composting were evaluated. It was found that not only is sawdust the most effective agent in reducing NH3 emissions, but that it also effectively promotes organic matter decomposition. Increases in the mixing ratio of sawdust in the range adopted in the present research, from 70% to 92% on a dry-weight basis, appeared to cause no adverse effects on the decomposition of sludge itself. And the higher the mixing ratio of sawdust, the more effective the reduction in NH3 emissions, however this effect was not enough to completely suppress these emissions, even at the highest mixing ratio.

Air Pollution↗

PubMed2001

A cryptic plasmid, pAO1, from a compost bacterium, Bacillus sp.

The complete nucleotide sequence of a new cryptic plasmid, pAO1 isolated from a compost bacterium Bacillus sp., has been analyzed. Analysis of the PCR-based 16S rRNA sequence showed the bacterium harboring pAO1 was closely related to Bacillus pallidus. The plasmid pAO1 was 3,325 bp in size. Two open reading frames, ORF1 and ORF2, encoding putative polypeptides of 248 and 290 amino acids, respectively, were identified within the sequence. The ORF1 has a limited sequence similarity to an integrase/recombinase, while the ORF2 has high similarity with the replication protein of pBC1 from Bacillus coagulans. A putative origin sequence for a plus-strand was located between ORFs. Southern blot analysis indicates this plasmid replicates via a rolling circle-type mechanism.

Bacillus↗

PubMed2001

Reconstruction of heavily calcified aorta and its visceral branches without extracorporeal circulation.

A 61-year-old Japanese female was referred to our hospital for surgical treatment of a localized heavily calcified abdominal aorta. Preoperative angiograms and computed tomograms revealed severe stenosis of the aorta, resembling a slit. Bypass grafting between the thoracic and abdominal aorta was successfully performed together with the reconstruction of the celiac artery, superior mesenteric artery, and bilateral renal arteries without extracorporeal circulation. Postoperative angiograms showed patency of the graft and branches. A localized heavily calcified abdominal aorta is relatively rare, and the cause of this entity might be Takayasu's aortitis.

Aged↗

PubMed2001

The characteristics of screened patients with abdominal aortic aneurysm.

BACKGROUND: Screening for abdominal aortic aneurysm (AAA) has not yet been established in Japan. We therefore report the characteristics of a screened population and discuss the implications of screening using ultrasound in Japan. METHODS: The subjects in our screening group were composed of 4428 participants who were 60 years of age or older. Aneurysm was detected in 16 cases, 15 males and 1 female, the detection rate being 0.4% in total and 0.9% in the males. We compare the characteristics of screened patients (n = 16) with non-screened patients operated on for abdominal aortic aneurysm (n = 166). RESULTS: There were no significant differences in the mean age or in the female ratio between the screened and non-screened groups (71 vs 70 y/o, 6% vs 13%, respectively). Solitary iliac aneurysms were significantly (p < 0.05) more frequent in the screened than in the non-screened group (19% vs 3%). The size of aneurysm in the screened group was significantly (p < 0.05) smaller compared with the non-screened group. Sixty-three per cent of the screened group and only 8% of the non-screened group had an aneurysm less than 40 mm in size. Aneurysm was palpable in only 31% of those of the screened group. There were no significant differences between the groups in the frequency of arteriosclerotic risk factors such as hypertension, ischaemic heart disease, diabetes mellitus, peripheral vascular disease and smoking habits. Surgical treatment was selected in 7 out of 16 screened patients. The remaining 9 patients with small-sized abdominal aortic aneurysms have been carefully followed up. CONCLUSIONS: Screening for abdominal aortic aneurysm using ultrasound is advisable especially for male participants and for the detection of iliac aneurysms. This screening procedure is useful for early detection because the screened aneurysm is generally small-sized and impalpable.

Aged↗

PubMed2001

Growth of the pulmonary arteries after systemic-pulmonary shunt.

Pulmonary artery growth after a systemic-pulmonary shunt was angiographically evaluated in 19 out of 35 patients. The mean age of the subjects at the time of the initial operation was 18+/-18 months including 12 patients under a year old. The preoperative diagnosis was tetralogy of Fallot (TOF) in 10 patients, TOF plus pulmonary atresia in five and transposition of great arteries in four. A Blalock-Taussig shunt (BTS) operation was performed in 16 patients (15 classical and 1 modified) and a central shunt was performed in three patients as an initial operation. The preoperative pulmonary artery index (PAI) was 129+/-42 in all patients and there were no significant differences between patients under or over a year old (139+/-42 vs. 115+/-49). Postoperative angiography was performed 32+/-13 months after the surgery. Room air arterial O2 pressure increased significantly from 29+/-5 mmHg to 42+/-5 mmHg just after an initial palliative shunt operation. PAI change in patients under a year old was 214+/-73%, which was higher than 145+/-27% in patients over a year old after a palliative shunt operation. On the ipsilateral side, PAI change was almost the same between patients under and over a year old. On the contralateral side, PAI change in patients under a year old was 216+/-68%, which was significantly higher than the 116+/-21% in patients over one year old. There was a significant negative correlation (r=-0.65, p<0.05) between PAI change and arterial O2 pressure as measured just after a palliative shunt operation. In conclusion, a palliative shunt operation prior to a year old is desirable in order to produce sufficient and bilateral pulmonary artery growth.

Anastomosis, Surgical↗

PubMed2000

Changes in gastric intramucosal pH and circulating blood volume following coronary artery bypass grafting.

PURPOSE: To determine the changes in gastric intramucosal pH (pHi) following coronary artery bypass grafting (CABG) in comparison with systemic hemodynamic variables and circulating blood volume (BVc). METHODS: Twenty patients who underwent CABG under mild hypothermic cardiopulmonary bypass (CPB) were included. Hemodynamic variables and the values of pHi were obtained at 3,6, 12 and 24 hr after admission to the intensive care unit (ICU). The pHi was measured by gastric tonometric catheter. The BVc was measured by carbon monoxide (CO)-labeled hemoglobin (CO-Hb) dilution method (CO method) at 6 and 24 hr after ICU admission. RESULTS: Systemic vascular resistance index (SVRI) and pulmonary vascular resistance index (PVRI) decreased with time. Systemic oxygen delivery index (DO2I) and systemic oxygen consumption index (VO2I) showed a gradual increase during the study period. By contrast, pHi decreased to the lowest value (7.26+/-0.05) at six hours and returned to normal levels (7.34+/-0.04) at 24 hr after ICU admission. Changes in BVc between six and 24 hr ranged from -242 ml to 978 ml (mean, 334+/-338 ml). The pHi increased in patients whose BVc increased by > 300 ml. Mean fluid balance was negative in this period (-386+/-667 ml; range, -1786 - + 423 ml). CONCLUSION: The pHi showed the lowest value at six hours and returned to normal at 24 hr after ICU admission. The pHi increased with the decrease in vascular resistance and with the increases in BVc in this period. The improvement of pHi, an indicator of splanchnic perfusion, appears to be related to systemic vasodilatation and an increase in BVc.

Aged↗

PubMed2000

Obesity and postoperative oxygenation after coronary artery bypass grafting.

OBJECTIVE: The relationship between obesity and postoperative oxygenation after coronary artery bypass grafting was studied. METHODS: Subjects were 68 patients undergoing solitary coronary artery bypass grafting--49 men and 19 women with a mean age of 64 years--divided into 3 groups by body mass index: group L with a body mass index of < 20 kg/m2 (n = 10), group M with a 20 < or = body mass index < 25 (n = 46), and group H with a 25 < or = body mass index (n = 12). Perioperative oxygenation was evaluated using respiratory indices measured preoperatively and 3 and 15 hours postoperatively. RESULTS: Postoperative respiratory indices significantly increased from 0.23 to 0.67 (p < 0.001) at 3 hours and to 0.97 (p < 0.01) at 15 hours postoperatively in group L, from 0.27 to 0.80 (p < 0.001) and to 0.94 in group M, and from 0.31 to 1.39 (p < 0.001) and to 1.45 in group H. The postoperative respiratory index in group H was significantly higher (p < 0.01) than that in groups M and L both at 3 and 15 hours postoperatively. Multivariate analysis showed that the coefficients of determination of body mass index to postoperative respiratory index, 23% at 3 hours and 16% at 15 hours postoperatively, were the highest among perioperative factors. CONCLUSIONS: Obesity is a major factor impairing postoperative oxygenation. Careful management in a semirecumbent position and/or nasal intermittent positive pressure ventilation may thus be required in obese patients.

Body Mass Index↗

PubMed2000

Postoperative oxygenation following coronary artery bypass grafting. A multivariate analysis of perioperative factors.

BACKGROUND: Pulmonary oxygenation is generally temporarily impaired following cardiac surgery. We studied the factors influencing postoperative oxygenation using multivariate analysis. METHODS: This study was retrospectively performed in University hospital. Fifty patients undergoing solitary coronary artery bypass grafting were included in this study. Patients were divided into two groups by mean age; older group (n=25) and younger group (n=25). Alveolar-arterial oxygen difference (A-aDO2) and respiratory index (RI) were measured at 3 hours after surgery and on postoperative day 1. Statistical analysis was performed using forward selection stepwise regression of 12 perioperative variables. RESULTS: In all patients, A-aDO2 and RI significantly (p<0.01) increased after surgery and remained high on POD1. In stepwise regression analysis, preoperative A-aDO2 and RI were significant factors in the equations for postoperative A-aDO2 and RI in general, which was the most important factor in the older group. In the older group, preoperative A-aDO2 or RI and water balance were significant (p<0.05) factors which were responsible for half the oxygenation impairment just after surgery, and PCWP showed a significant (p<0.01) negative correlation with both A-aDO2 and RI on POD1. In the younger group, PCWP was a significant (p<0.01) factor for A-aDO2 and CVP and CI were significant for RI on POD1. CONCLUSIONS: Postoperative oxygenation was mainly influenced by the preoperative respiratory condition, especially in old patients, indicating that preoperative management by a physiotherapist may be necessary. Pleurotomy also had a negative influence. Careful intraoperative and postoperative volume control is important in old patients.

Adult↗

PubMed2000

Postoperative splanchnic perfusion following the reconstruction of thoracoabdominal aortic aneurysm involving abdominal visceral branches. Report of a case.

A 58-year-old man with thoracoabdominal aortic aneurysm involving visceral arteries underwent graft replacement of the thoracoabdominal aorta and associated reconstruction of abdominal visceral branches. Femoro-femoral extracorporeal bypass, intermittent selective visceral arterial perfusion and a staging cross-clamping method of the aorta were utilized at surgery. The total cross-clamping time of the aorta was 165 minutes. The patient's postoperative course was uneventful with no incidence of hepatic and renal failure or paraplegia. Although postoperative systemic blood pressure and cardiac output recovered to normal values within 7 hrs after the release of aortic clamping, it took 18 hrs for hepatic venous hemoglobin oxygen saturation (ShvO2) to recover. Base excess in arterial blood, lactic acid in arterial and hepatic venous blood, and ketone body ratio in arterial blood (AKBR) and hepatic venous blood (HVKBR) recovered to within normal ranges after 18 hrs of the release of aortic clamping. ShvO2 monitoring is a simple and may be a useful parameter in evaluating postoperative splanchnic perfusion and predicting abdominal organ failure at the time of thoracoabdominal aortic reconstruction involving visceral arteries.

Aortic Aneurysm, Abdominal↗

PubMed2000

The effect of short-term coronary perfusion using oxygenated diluted blood following cold storage for long-term heart preservation.

BACKGROUND: The aim of this study was to compare the results obtained from the use of both University of Wisconsin (UW) solution and diluted blood in short-term coronary perfusion following 12-hour cold storage. METHODS: Following coronary vascular washout of adult mongrel dogs with the UW solution, the heart was excised and immersed in a cold (4 degrees C) UW solution for 12 hours followed by 1-hour of coronary perfusion. Two different solutions were used for the coronary perfusion; a 4 degrees C oxygenated UW solution (Group U, n=7) and 15 degrees C oxygenated diluted blood (Group B, n=7). Myocardial high energy phosphate (HEP) levels, tissue water content (TWC), interstitial tissue space (ITS) rates and histological findings were evaluated at 0- and 12-hour cold storage and also following coronary perfusion. The preserved graft was then evaluated through orthotopic transplantation. The control group in this experiment consisted of seven hearts transplanted after 12-hour cold storage without coronary perfusion. RESULTS: Myocardial HEP levels significantly decreased after 12-hour cold storage. The recovery rate of myocardial HEP levels after coronary perfusion was significantly (p<0.05) higher in Group B than in Group U. The increase of myocardial TWC during coronary perfusion was significantly (p<0.01) higher in Group B than in Group U. After 1-hour coronary perfusion, the subendocardial ITS rate was significantly (p<0.01) higher compared with the value at 0-hour cold storage in Group U, whereas it demonstrated no significant change in Group B. PAS stain revealed the glycogen content of the subendocardial tissues was higher in Group B than in Group U. The recovery rate of hemodynamic parameters 2 hours after heart transplantation was higher in Group U and significantly (p<0.05) higher in Group B than in the control. CONCLUSIONS: Myocardial HEP levels recovered significantly after additional coronary perfusion. Though the UW solution prevented myocardial cellular edema, subendocardial perfusion was incomplete and the recovery rate of myocardial HEP levels was lower, suggesting that diluted blood may become the solution of choice as a perfusate.

Adenosine↗

PubMed1999

Abdominal Aortic Dilatation in Japanese Residents.

The correlation between abdominal aortic dilatation and arteriosclerotic risk factors was studied in 2514 Japanese residents (947 men, 1567 women, mean age 70 years old). The aortic diameter was measured by ultrasound and an aortic dilatation was defined as above 30 mm in diameter, including abdominal aortic aneurysm (AAA). Forty-three (1.7%) patients with a dilated aorta and 2471 with a normal-sized aorta were compared. Abdominal aortic dilatation was significantly (p < 0.01) more frequent in men than in women (3% vs 0.7%). Obesity and hyperlipidemia were slightly (p < 0.1) more frequent in patients with a dilated aorta than in those with a normal-sized aorta. There were no significant differences between the two groups in mean age, frequency of smoking, diabetes mellitus, and coronary artery disease. In conclusion, male obesity and hyperlipidemia may be risk factors for aortic dilatation in Japan. Women may not be screened because of cost-effectiveness. The prevalence of aortic dilatation in Japan was lower than in European countries. However, screening for AAA using ultrasound would be advantageous when considering the grave prognoses of ruptured AAA.

Journal Article↗

PubMed1999

Thoracoscopic resection of intrathoracic vagus neurofibroma.

A thoracoscopic resection of mediastinal neurofibroma originating from the intrathoracic vagus nerve was successfully performed in an 18-year-old female. This report reviews the clinical and morphological features of intrathoracic vagus neurofibroma. Often neurofibroma has multiple lesions and/or multinodular shape. Thoracoscopic resection is a useful treatment for patients with intrathoracic neurofibroma, although careful observation is necessary when performing a radical resection.

Adolescent↗

PubMed1999

Primary cardiac angiosarcoma associated with cardiac tamponade: case report.

A 57-year-old male with primary cardiac angiosarcoma was initially admitted for cardiac tamponade. Pericardiocentesis was performed twice preoperatively, but the bloody pericardial fluid was cytologically negative for malignant cells. The tumor in the right atrium was resected during cardiopulmonary bypass. The resected tumor was 5.5x4.5x3.0cm in size and the diagnosis of cardiac angiosarcoma was made histologically. There were no tumor cells in the surgical margin. Unfortunately the patient died 3.5 months after surgery due to multiple recurrence in the pericardium. A suitable therapy for cardiac angiosarcoma is still controversial, but early antemortem diagnosis and more aggressive combined treatment should be considered.

Cardiac Tamponade↗