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Biomedical subjects

T Tamura

Publications and source records attributed to T Tamura.

At least 361 records · Page 20Linked to original sources
PubMed1998

Long-term heart rate fluctuations in postoperative and brain-dead patients.

Long-term heart rate fluctuations in postoperative and brain-dead patients were investigated. Heart rates were monitored continuously, and the data were stored, edited, and interpolated to allow for data lost during calibration and disconnection of the sensors for various treatments. Heart rate power spectra were calculated using the fast Fourier transform method. The power spectra of the patients who recovered showed that the heart rate fluctuated and produced a 1/f relationship, termed 1/f fluctuations, whereas those of patients who died in the intensive care unit (ICU) consisted of white-noise-like signals. The power spectra in brain-dead patients showed a 1/f relationship under steady-state conditions, while the power density and variation of the frequency distribution were lower than those in a normal subject. Therefore, 1/f fluctuations appear to be universal and occur independent of the central nervous system.

Blood Pressure↗
PubMed1998

Trienzyme treatment for food folate analysis: optimal pH and incubation time for alpha-amylase and protease treatment.

Recent reports have indicated that trienzyme treatment before folate determination is essential to obtain the proper folate content in foods. Trienzyme treatment is performed by using alpha-amylase and protease for folate extraction from carbohydrate and protein matrices, and folate conjugase for the hydrolysis of polyglutamyl folates. We evaluated the conditions of pH and incubation time for the treatment with alpha-amylase and protease. Four food items, including fresh beef, white bread, cow's milk, and fresh spinach, were selected for this investigation. We found that optimal pHs for alpha-amylase treatment of beef and cow's milk were 7.0 and 5.0, respectively, whereas those for white bread and spinach were not distinctive at pHs from 2.0 to 7.0. The optimal incubation time for alpha-amylase was 4 h for fresh beef and cow's milk, whereas no distinctive optimal incubation period was found for white bread and fresh spinach. Our data indicate that the conditions for enzyme treatments vary depending on food items. Trienzyme treatment resulted in an increase of more than 50% in the mean folate content over folate conjugase treatment alone. It is necessary to treat food samples with not only traditional folate conjugase, but also with alpha-amylase and protease before folate determination to obtain the actual folate content.

Animals↗
PubMed1998

Fully automated health monitoring at home.

The aim of this study was to provide adequate home health monitoring for the elderly at home using fully automated signal measurement with personal identification to support daily health care and to improve quality of life. We attempted to develop a home health monitoring system that did not provide any restrictions during sleep, bathing and excretion. A new room including bath and toilet was constructed. The system consisted of monitoring devices and a computer terminal for collecting data. The data were automatically obtained from monitoring devices situated at the bed, bath and toilet and were transferred to a data terminal and stored for further analysis. Where subjects live with their spouse or family, personal identification is required to store data individually. For the bathtub data, personal identification was performed using ECG data. Sampled data were reduced by wavelet transform and distinguished by a neural network. The data acquisition system is now underway and data are being extensively collected.

Aged↗
PubMed1998

[Carbon monoxide concentrations during low flow anesthesia].

Elevated carbon monoxide (CO) concentrations have been reported during general anesthesia using inhaled anesthetics. In order to assess the safety of low flow anesthesia, we examined CO concentrations in anesthesia circuit during low flow anesthesia. Thirty patients were randomly divided into two groups. Anesthesia was induced with intravenous thiopental 5 mg.kg-1 and maintained with oxygen 2 l.min-1, nitrous oxide 4 l.min-1 and isoflurane (group H) or oxygen 0.5 l.min-1, nitrous oxide 0.5 l.min-1 and isoflurane (group L). The concentrations of CO in exhaust gas of anesthetic gas monitor were examined by CO sensor (XC-341, Shinkosumosudenki, Tokyo) and COHb was analyzed. The concentrations of CO in group L were significantly higher than in group H. The highest value, however, was 30 ppm. The COHb levels were slightly higher in group L, but the highest value was 2.1%. We consider that these results show no clinical risk and low flow isoflurane anesthesia may be performed safely. Measuring the CO concentrations is helpful for the safety of low flow anesthesia.

Aged↗
PubMed1998

Enhanced expression of a new class of liver-enriched b-Zip transcription factors, hepatocarcinogenesis-related transcription factor, in hepatocellular carcinomas of rats and humans.

Rat hepatocarcinogenesis-related transcription factor (HTF) was earlier identified as a b-Zip transcription factor in chemically induced rat hepatocellular carcinoma (HCC) by cDNA subtraction, and its structure was found to be different from that of the conventional b-Zip proteins. We investigated htf gene expression in rat tissues by Northern analysis and found that HTF expression was ubiquitous but was enriched in the liver. HTF expression increased concomitantly with HCC development in rat liver, and the HTF-containing DNA-binding factor also increased. Stimulated HTF gene expression also was observed in rat regenerating livers. From the results of various assays, X-box-binding protein 1/Tax-response element binding factor 5 was suggested to be a human homologue of rat HTF. In humans, HTF gene expression was also abundant in the liver and was revealed to be specifically stimulated in HCCs, but not in other types of cancers. To our knowledge, HTF is the first example of a liver-enriched transcription factor that exhibits HCC-associated gene expression. Injection of anti-HTF antibody decreased the growth rate of cultured HCC cells. Consequently, HTF is thought to participate in hepatocyte growth as well as in hepatocarcinogenesis.

Animals↗
PubMed1998

[Clinical evaluation of cholesterol embolization syndrome after cardiac catheterization].

The clinical features and outcomes of patients with cholesterol embolization syndrome after cardiac catheterization were evaluated. Among 4,920 patients undergoing cardiac catheterization during 1991 to 1996, the symptoms, signs, laboratory data, treatment and prognosis of eight (6 males and 2 females, mean age 69 years old) were reviewed who were pathologically or clinically diagnosed as having cholesterol embolization syndrome. All patients had more than two coronary risk factors. Mobile plaque of the aortic arch was detected in all five patients who underwent transesophageal echocardiography. All patients had one or more precipitating factors, including coronary angiography, percutaneous transluminal coronary angioplasty, cardiovascular surgery and cardiopulmonary resuscitation. The first symptom was renal dysfunction in four patients, skin findings of purple toes in two, muscle pain in one and new onset of refractory hypertension in one. The time after the precipitating factor to the onset of symptoms was 32 +/- 9 days on average. Eosinophilia was found in all patients and six patients revealed eosinophilia before the onset of symptoms. Four patients showed skin findings of purple toes which progressed in three of the four patients even after anticoagulant therapy was discontinued. Epidural anesthesia was markedly effective for skin findings of purple toes in two of the three patients. Diagnosis of cholesterol embolization syndrome is difficult because patients show various symptoms and there is an interval between the precipitating factor and the onset of symptoms. However, the conditions of the patients deteriorate rapidly and the prognosis is generally poor without supportive therapy in the early stage. Our study demonstrated that eosinophilia might be an important clue to early detection of cholesterol embolization syndrome. Furthermore, epidural anesthesia is effective for skin findings of purple toes in patients with cholesterol embolization syndrome. In conclusion, cholesterol embolization syndrome should be detected in the early stage based on eosinophilia or clinical symptoms after cardiac catheterization, and supportive therapy started as soon as possible, including discontinuance of anticoagulant therapy, hemodialysis for renal dysfunction and epidural anesthesia for skin findings of purple toes.

Aged↗
PubMed1998

[Palmaz-Schatz stent implantation for aorto-ostial stenoses of native coronary arteries and saphenous vein grafts].

Conventional balloon angioplasty treatment of aorto-ostial stenoses in native coronary arteries and saphenous vein grafts is associated with a low primary success rate, a high complication rate and a high incidence of restenosis. The short-term outcome of Palmaz-Schatz stent implantation in aorto-ostial lesions was compared with that of balloon angioplasty. Thirteen patients underwent stent implantation for 13 de novo lesions (four in the left main coronary trunk, two in the right coronary artery, seven in the vein graft) between January 1994 and December 1995. Fourteen patients underwent balloon angioplasty for 14 de novo lesions (five in the left main coronary trunk, four in the right coronary artery, five in the vein graft between January 1986 and April 1992. Both groups had similar clinical characteristics. Initial success was obtained in all patients in the stent group, compared with 71% of the balloon angioplasty group. Insufficient dilation was the main cause for such failure in the balloon angioplasty group. Baseline reference diameters were similar (3.40 +/- 0.65 mm in the stent group vs 3.36 +/- 0.42 mm in the balloon angioplasty group) and there was no difference in baseline minimal luminal diameter (1.41 +/- 0.74 vs 1.08 +/- 0.56 mm). Minimal luminal diameter was significantly greater in the stent group than in the balloon angioplasty group at both post-procedure and follow-up examinations (post: 3.36 +/- 0.58 vs 2.69 +/- 0.45 mm, p < 0.01; follow-up: 2.33 +/- 0.96 vs 1.52 +/- 0.68 mm, p < 0.05). There was no subacute occlusion in either group. The overall angiographic restenosis rate (> 50% stenosis) was lower in the stent group (17%) than in the balloon angioplasty group: the restenosis rates of native lesions were 0% in the stent group and 40% in the balloon angioplasty group; those of saphenous vein graft lesions were 33% in the stent group and 50% in the balloon angioplasty group. Although the number of patients was limited, these results suggest that Palmaz-Schatz stent implantation may be a safe and effective strategy for treating aorto-ostial lesions in both native coronary arteries and saphenous vein grafts.

Angioplasty, Balloon, Coronary↗
PubMed1998

[Hypertrophic obstructive cardiomyopathy in an elderly patient manifesting as refractory congestive heart failure of acute onset: a case report].

An 84-year-old woman was admitted to our hospital because of left heart failure of acute onset. Transthoracic echocardiography showed diffuse hypertrophy of the normal sized hyperkinetic left ventricle and chordae-like fluttering echoes attached to the mitral valve with severe mitral regurgitation signals. Mosaic flow signals were seen at the left ventricular outflow tract, but the velocity could not be measured. Emergent transesophageal echocardiography detected no obvious mitral valve prolapse. Cardiac catheterization showed greater than 100 mmHg pressure gradient between the left ventricle and femoral artery. Pressures in the femoral artery and pulmonary capillary wedge changed reciprocally in the intensive care unit; a bisferient narrow pulse pressure of the femoral artery was associated with increased v wave of the pulmonary capillary wedge pressure, and a wide pulse pressure of the femoral artery with absent v wave of the pulmonary capillary wedge pressure. Pressure monitoring in the intensive care unit, catheterization laboratory and transesophageal echocardiography were useful to understand the pathophysiology of the patient.

Aged↗
PubMed1998

[Carbon monoxide in the expiratory gas during laparoscopic surgery].

One of the complications of laparoscopic surgery is carbon monoxide (CO) production under the use of electrocautery. We experienced a case in which high levels of CO were detected in the expiratory gas. An 80-year old, 33 kg female was scheduled for laparoscopic nephrectomy. Anesthesia was induced with thiopental and vecuronium and maintained with nitrous oxide 60% in oxygen and isoflurane. The concentrations of CO in the anesthetic circuit were examined with CO sensor (XC-341, Shinkosumosudenshi, Tokyo). The CO concentrations were not detected at the start of operation. About 140 minutes after carbon dioxide pneumoperitoneum, the CO concentration increased up to 170 ppm accompanying a high Paco level. The high concentrations, however, decreased immediately after ending of pneumoperitoneum. The HbCO levels were unchanged. Subcutaneous emphysema was noted at the end of surgery. This is because CO is more absorbable in the subcutaneous tissue than in the peritoneal cavity. We consider that CO was absorbed in subcutaneous emohysema during pneumoperitoneum and exhausted in the expiratory gas. When subcutaneous emphysema occurred during laparoscopic surgery, we should be aware of absorption of CO.

Aged↗
PubMed1998

[Metastatic renal tumor originating from esophageal carcinoma: a case report].

We report a case of renal metastasis from esophageal carcinoma. The patient was a 74-year-old man, who had undergone an operation for esophageal carcinoma thirteen months previously. He was admitted to our clinic for examination of a right renal mass. Computed tomography (CT) revealed an irregular low density area in the right kidney and angiography showed a hypovascular tumor. Partial nephrectomy was performed. Histological examination revealed squamous cell carcinoma and the diagnosis was metastasis of esophageal carcinoma. Metastatic renal tumors are rarely encountered clinically and, to our knowledge, the present case is only the 16th clinical report of the renal metastasis of esophageal carcinoma in Japan. However, metastasis to the kidney is relatively common at autopsy. It is the fifth most common site of metastasis following the lungs, liver, bones and adrenals. Consequently, patients with malignancy should be followed up while keeping renal metastasis in mind.

Aged↗
PubMed1998

Gene expression in hepatomas.

Gene expression changes in accordance with cell growth, differentiation and carcinogenesis. To elucidate the molecular mechanisms for hepatocarcinogenesis as well as maintenance of normal hepatocytes, it is important to identify the genes that have altered expression with carcinogenesis. We established a new and efficient cDNA subtraction method via two cDNA populations. By using this method along with rat hepatomas made by the Solt-Farber protocol, we identified a number of genes, some of which are activated in hepatocellular carcinoma (HCC). These genes include ones which code for a transcription factor and a metabolic enzyme. One particular gene can be used as a tumour marker. Our method is beneficial for the isolation of a wide range of HCC-related genes in rats which, in turn, enables easy identification of their human counterparts. In this review, we describe details of our method and the isolated genes. We also briefly describe transcription factors in the liver.

Animals↗
PubMed1998

[Epidural anesthesia for cesarean section in a twin pregnant patient with severe aortic stenosis].

A 35-year-old twin primigravida with aortic stenosis underwent cesarean section under epidural anesthesia. She had her ventricular septal defect repaired at 3 years of age. Preoperative ultrasonic study revealed severe aortic stenosis in which valve area was 0.77 cm2 and pressure gradient between the left ventricle and the aorta was 80 mmHg. We persuaded her and her husband to discontinue pregnancy and recommended aortic valve replacement surgery. They rejected our suggestions, and cesarean section was scheduled at 29 weeks' gestation. We chose epidural anesthesia. A 20-gauge catheter and a pulmonary artery catheter were inserted to monitor the hemodynamics. Two lumbar epidural catheters were placed at the L 1-2 and L 4-5 intervertebral spaces. Sixteen milliliters of 1.5% mepivacaine were injected, producing anesthesia up to T 6 level. The babies were delivered, and postnatal conditions of both infants were satisfactory. Methoxamine 1 mg was administered four times when systolic blood pressure decreased to 80 mmHg following deliveries. Otherwise, peripartal hemodynamics was stable, and she was transferred to the intensive care unit (ICU). Postoperative pain was controlled with epidural infusion of fentanyl. She did not complain of chest pain perioperatively and was discharged from the ICU next day.

Adult↗
PubMed1998

[A case of renal pelvic carcinoma in a completely duplicated pelvis and ureter].

We report a case of renal pelvic carcinoma with a completely duplicated pelvis and ureter. A 72-year-old man was referred to our hospital because of asymptomatic and macroscopic hematuria. Excretory urography and retrograde pyelography revealed a tumor in the left upper renal unit of a completely duplicated pelvis and ureter. Left total nephroureterectomy was performed. Histological diagnosis was transitional cell carcinoma. This is the 8th case of upper urotherial tumor occurring in a completely duplicated pelvis and ureter in the Japanese literature.

Aged↗
PubMed1997

HUB1, a novel Krüppel type zinc finger protein, represses the human T cell leukemia virus type I long terminal repeat-mediated expression.

We have shown that human T-cell leukemia virus type I (HTLV-I) gene expression is negatively regulated by the U5 repressive element (U5RE) of its long terminal repeat (LTR). To isolate factors binding to U5RE, we screened a cDNA expression library by south-western blotting with a U5RE probe. Screening 2 x10(6) clones gave a positive clone with a 3.8 kb insert encoding a novel 671 residue polypeptide, named HTLV-I U5RE binding protein 1 (HUB1), with five zinc finger domains and a Krüppel-associated box like domain; HUB1 may be related to a repressor belonging to the Krüppel type zinc finger protein. A 4.0 kb mRNA for HUB1 is ubiquitously expressed among all human tissues tested. HUB1 recognizes the TCCACCCC sequence as a core motif and exerts a strong repressive effect on HTLV-I LTR-mediated expression. A new repressive domain, named HUB1 repressive (HUR) domain, was identified, rather than the Krüppel-associated box like domain. The N-terminal region upstream of HUR domain seemed to be also indispensable to the repression. Thus, we propose that HUB1 is a new type repressor and plays an important role in the HTLV-I U5-mediated repression.

Amino Acid Sequence↗
PubMed1997

Determination of methylation specificity of sequence-specific DNA methyltransferases using matrix assisted laser desorption/ionization time-of-flight mass spectrometry.

We describe here a sensitive and straightforward method for characterizing the methylation specificity of type II DNA methyltransferase (MTase) using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. DNA substrate, prepared by ligation of a commercially available oligonucleotide, was modified by the subject MTase, and was derivatized to a mixture of single-stranded oligonucleotides through endonuclease treatment, heat-denaturation and limited digestion by 3'-terminus-specific phosphodiesterase I. MALDI-TOF mass spectrometry was used to determine the mass differences between the digestion products, and the methylated nucleotide was explicitly identified by the mass increase of 14 Da due to the base modification. The method was applicable to the three representative MTases M. Eco RI, M. Bam HI and M. Hae III.

Base Sequence↗