Biomedical subjects

K Doi

Publications and source records attributed to K Doi.

At least 37 records · Page 2Linked to original sources

PubMed2000

Free vascularized bone graft for nonunion of the scaphoid.

We used a free vascularized small periosteal bone graft to treat scaphoid nonunion. The graft consisted of periosteum, full-thickness cortex, and the underlying cancellous bone and was harvested from the supracondylar region of the femur. The graft was nourished by the articular branch of the descending geniculate artery and vein. Unlike the currently used vascularized bone grafts, this graft can be easily harvested and shaped to accommodate the bone defect of the scaphoid without disturbing its vascularity and can then be transferred with microvascular anastomosis of the nutrient vessels to the radial artery and its venae commitantes. Ten patients with longstanding nonunion of the scaphoid secondary to avascular necrosis, confirmed by radiologic and intraoperative findings, were treated with this vascularized bone graft. Union was achieved in all 10 patients at an average of 12 weeks after surgery. The average follow-up period for all fractures was 3.5 years. The scores for overall outcome, according to the Mayo wrist scoring system, were excellent in 4 patients, good in 4, and fair in 2. Two unsatisfied patients had preoperative signs of early periscaphoid osteoarthrosis. This free vascularized small bone graft from the supracondylar region of the femur is an attractive alternative to the conventional vascularized bone grafting procedures.

Adolescent↗

PubMed2000

Experience with the pedicled latissimus dorsi flap for finger reconstruction.

The pedicled latissimus dorsi flap was used for the reconstruction of finger function in 12 patients with severely disabled hands. The fascial origin of the muscle was sutured directly to finger flexors in 6 patients, and to extensors in the other 6 patients in the forearm without severing the neurovascular pedicle. Voluntary contraction of the muscle was obtained in all patients. Useful tendon gliding was achieved in 6 patients, thereby providing total active motion of fingers of >100 degrees. In the remaining 6 patients, however, several problems such as stiff finger joints prevented appropriate tendon gliding, resulting in total active motion of <60 degrees. When these problems are overcome, the pedicled latissimus dorsi muscle can yield satisfactory excursion for extrinsic tendons of the fingers. In contrast to free muscle transplantation, early and predictable recovery of function can be obtained using this particular technique without any risk of denervation of the muscle.

Adolescent↗

PubMed2000

The role of the body mass index and triglyceride levels in identifying insulin-sensitive and insulin-resistant variants in Japanese non-insulin-dependent diabetic patients.

Using the minimal model approach shown by Bergman, our group had previously shown 2 variants among non-obese mildly diabetic patients, one with normal insulin sensitivity and the other with insulin resistance. The present study examines whether these 2 variants exist in the ordinary Japanese non-insulin-dependent diabetes mellitus (NIDDM) population and compares the clinical profile between the 2 discrete forms of NIDDM. In addition, we investigated the factors responsible for insulin resistance observed in Japanese NIDDM populations. One hundred eleven untreated Japanese NIDDM subjects (fasting glucose < 10 mmol/L) were assessed for insulin action (homeostasis model assessment [HOMA-IR] = fasting serum insulin (microU/mL) x fasting plasma glucose (mmol/L)/22.5) and the fasting lipid profile. Sixty percent of these patients had normal insulin sensitivity (HOMA-IR < 2.5). The insulin-resistant patients had higher serum cholesterol (188.1 +/- 5.2 v 182.2 +/- 3.9 mg/dL, P> .05) and low-density lipoprotein (LDL) cholesterol (501.2 +/- 16.7 v 469.4 +/- 14.8 mg/dL, P > .05) than the insulin-sensitive patients, but the difference was not statistically significant. In contrast, the former group had a significantly higher body mass index ([BMI] 26.6 +/- 0.8 v 21.7 +/- 0.4 kg/m2, P < .0001) and higher serum triglycerides (181.0 +/- 16.4 (range, 79 to 545) v 95.1 +/- 4.1 (range, 36 to 204) mg/dL, P < .0001) and lower high-density lipoprotein (HDL) cholesterol (47.2 +/- 1.7 v 58.2 +/- 2.5 mg/dL, P < .005) than the latter group. HOMA-IR was related to the BMI. Fifteen of 17 (88%) NIDDM patients with a BMI greater than 27.0 were insulin-resistant, whereas 35 of 38 (92%) NIDDM patients with a BMI less than 21.5 were insulin-sensitive. In the midrange BMI (21.5 to 27.0 kg/m2), patients were equally likely to be insulin-resistant or insulin-sensitive. Analysis of the midrange BMI group showed that HOMA-IR was associated with serum triglycerides (P < .0001) but not with the BMI. These data suggest the following conclusions: (1) Japanese NIDDM patients can be classified into 2 populations, one with normal insulin sensitivity and the other with insulin resistance; (2) NIDDM patients with normal insulin action have a low cardiovascular disease risk factor, whereas those with insulin resistance have a markedly increased cardiovascular disease risk factor; and (3) the BMI and serum triglyceride level per se are associated with insulin action in Japanese NIDDM populations.

Adult↗

PubMed2000

The diagnostic value of intraoperative measurement of choline acetyltransferase activity during brachial plexus surgery.

We used the measurement of choline acetyltransferase (CAT) activity to distinguish between preganglionic and postganglionic injuries of the spinal roots during brachial plexus surgery. This study includes ten spinal roots in six patients with traumatic brachial plexus injuries. The results of CAT activity were compared with myelographic findings, the operative findings and the intraoperative evoked spinal cord potentials. The results of CAT activity and the operative findings were consistent in all roots. Whereas CAT activity in fascicles in preganglionic injured roots was below 500 cpm, it was above 2000 cpm in postganglionic injured roots. This study shows that intraoperative measurement of CAT activity can provide useful information on the site and severity of brachial plexus injuries and the assessment of the motor function status of the injured spinal root, both directly and quantitatively.

Adult↗

PubMed2000

Reconstruction of hip abduction using free muscle transplantation: a case report and description of the technique.

The authors describe a free-functioning latissimus dorsi muscle transplantation for reconstruction of hip abduction. A radical "buttockectomy" was performed on a 62-year-old patient with recurrent soft-tissue sarcoma. The patient received a muscle transplantation immediately after resection of the tumor. Until recovery of the muscle, a complete absence of hip abductors resulted in a marked lurch in the patient's gait, requiring him to use walking aids. Reinnervation of the muscle was confirmed via electromyography 6 months after surgery. Hip abduction was restored along with muscle recovery, and walking support was no longer required. Although the strength of the muscle was not sufficiently powerful to overcome gravity fully, the latissimus dorsi muscle improved markedly the performance of an otherwise unstable hip. This patient demonstrates that microsurgical reconstruction is of great value in enhancing the functional outcome of a salvaged limb after tumor surgery.

Biomechanical Phenomena↗

PubMed2000

A case of local recurrent pheochromocytoma: usefulness of I-123 MIBG early SPECT and maximum intensity projection images.

It has been reported that 10% of patients with pheochromocytoma experience recurrence despite surgery. The authors administered I-123 MIBG to patients with recurrent pheochromocytoma and found that early images are more useful than delayed images to detect recurrence. Early imaging with I-123 MIBG is useful for postoperative follow-up studies in patients with pheochromocytoma and those with possible tumor recurrence.

3-Iodobenzylguanidine↗

PubMed2000

Tc-99m PMT whole-body scintigraphy for evaluated of therapeutic effect and for monitoring bone metastasis in a patient with hepatocellular carcinoma.

Detection of metastatic lesions by bone scintigraphy is highly sensitive but has a low rate of specificity. Often bone metastases from hepatocellular carcinoma are not detected by bone scintigraphy because of low uptake or a photopenic area in the tumor. In contrast, Tc-99m Sn-N-pyridoxy-5-methyltryptophan (Tc-99m PMT) whole-body scintigraphy reflects tumor viability, and the specificity of detection is so high that tumor structure can be shown well. Tc-99m PMT whole-body scintigraphy was helpful for evaluating the response to therapy and monitoring the course of the patient described here with bone metastasis from hepatocellular carcinoma.

Bone Neoplasms↗

PubMed2000

Oxidative stress augments secretion of endothelium-derived relaxing peptides, C-type natriuretic peptide and adrenomedullin.

OBJECTIVE: Excess oxidative stress is one of the major metabolic abnormalities on vascular walls in hypertension and atherosclerosis. In order to further elucidate the endothelial function under oxidative stress, the effect of hydrogen peroxide (H2O2) on expression of two novel endothelium-derived vasorelaxing peptides, C-type natriuretic peptide (CNP) and adrenomedullin (AM) from bovine carotid artery endothelial cells (BCAECs) was examined. METHODS: BCAECs were treated with H2O2 (0.1-1.0 mmol/ l) and/or an antioxidant, N-acetylcysteine (NAC) (5-10 mmol/l), and incubated for 48 h. The concentrations of CNP and AM were measured with the specific radioimmuno assays that we originally developed. CNP and AM mRNA expressions were also examined by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Treatment of BCAECs with 0.5 and 1 mmol/l H2O2 induced 9-and 10-fold increases of CNP concentration in the media. Addition of 10 mmol/l NAC significantly suppressed the effect of H2O2 by 52%. RT-PCR analysis showed that CNP mRNA expression in BCAECs was also rapidly augmented within 1 h with H2O2 (1 mmol/l) treatment, and reached a peak at 3 h to show a 10-fold increase. AM secretion from BCAECs also increased to two-fold with exposure to 0.5 mmol/l H2O2, accompanied with the augmented level of AM mRNA. NAC 10 mmol/l completely suppressed the effect of H2O2 on AM secretion. CONCLUSIONS: In this study, it has been demonstrated that H2O2 augments endothelial secretion of the two endothelium-derived relaxing peptides, CNP and AM. Our findings suggest the increased secretion of CNP and AM from endothelium under oxidative stress may function to compensate the impaired nitric oxide-dependent vasorelaxation in hypertension and atherosclerosis.

Acetylcysteine↗

PubMed2000

Altered gene expression of uncoupling protein-2 and -3 in stroke-prone spontaneously hypertensive rats.

BACKGROUND: Uncoupling proteins (UCPs) are the inner mitochondrial membrane-associated proteins, which dissipate the proton gradient and generate heat instead of ATP. The involvement of UCPs in energy expenditure and glucose metabolism has been suggested. Recently, we succeeded in cloning of rat UCP2 and UCP3. OBJECTIVE: The aim of this study was to elucidate the pathophysiological role of UCP2 and UCP3 in hypertension associated with hyperglycemia in stroke-prone spontaneously hypertensive rats (SHR-SP). METHODS: UCP2 and UCP3 mRNA levels of cardiac and gastrocnemius muscles in SHR-SP and Wistar-Kyoto (WKY) rats were determined at 6 weeks (prehypertensive stage) and at 15 weeks (hypertensive stage). RESULTS: UCP2 and UCP3 mRNA levels in the heart of SHR-SP at 6 weeks were significantly higher than those of WKY rats (1.6-fold, 3.6-fold, respectively). These tendencies did not change in the heart at 15 weeks. UCP2 and UCP3 mRNA levels in the skeletal muscle of SHR-SP at 6 weeks were significantly higher than those of WKY rats (1.4-fold, 2.4-fold, respectively). In contrast, at 15 weeks, UCP2 and UCP3 mRNA levels in the skeletal muscle of SHR-SP were significantly lower than those of WKY rats (70 and 36% of WKY rats, respectively). Therefore, the decrease of UCP2 and UCP3 in the skeletal muscle was observed with the concomitant development of hypertension in SHR-SP. UCP2 mRNA levels in the epididymal fat of SHR-SP at 15 weeks were similar to that of WKY rats. CONCLUSIONS: Altered gene expression of UCP2 and UCP3 might be related to some pathophysiological aspects in hypertension and glucose metabolism in SHR-SP.

Adipose Tissue↗

PubMed2000

Improved contralateral subtraction images by use of elastic matching technique.

A contralateral subtraction technique has been developed to assist radiologists in the detection of asymmetric abnormalities such as lung nodules on a single chest radiograph. With this technique, a contralateral subtraction image is obtained by subtracting a right/left reversed "mirror" image from the original one. The lesions in the subtraction image may be enhanced because most of the symmetric skeletal structures, such as peripheral ribs, are eliminated. Although the quality of the previous contralateral subtraction images is relatively good, severe misregistration artifacts, mainly due to serious asymmetry of the ribs in the two lungs of the original image, were observed in some cases, and minor misregistration artifacts were also observed in many cases. In this study, we employed three image warping techniques. An initial global warping technique was applied to reduce severe misregistration artifacts in the subtraction image caused by asymmetric rib structures. Additional two iterative warping techniques based on an elastic matching technique were used for accurate registration of the local structures of ribs, so that minor artifacts present in many subtraction images obtained with the previous technique were greatly reduced. With the new technique, the percentage of chest images, which were rated as being of adequate, good, or excellent quality of subtraction images by use of a subjective evaluation method, was improved from 91% to 97%. In particular, the number of cases with excellent quality was greatly increased from 15% to 42%. The contralateral subtraction technique can be used for detection of asymmetric abnormalities, such as lung nodules, pneumothorax, pneumonia, and emphysema, on peripheral lungs in single chest radiographs, and it therefore has potential utility in a large proportion of abnormal chest images.

Algorithms↗

PubMed2000

Contralateral subtraction: a novel technique for detection of asymmetric abnormalities on digital chest radiographs.

A novel contralateral subtraction technique has been developed to assist radiologists in the detection of asymmetric abnormalities on a single chest radiograph. With this method, the lateral inclination is first corrected by rotating and shifting the original chest image so that the midline of the thorax is aligned with the vertical centerline of the original chest image. The rotated image is then flipped laterally to produce a reversed "mirror" image. Finally, the mirror image is warped and subtracted from the original image for derivation of the contralateral subtraction image. The three key techniques which are employed in this study are applied successively to the initial contralateral subtraction technique for acquisition of improved subtraction images. One hundred PA chest radiographs, including 50 normals and 50 abnormals, were used as the database for this study. The percentage of chest images, which were rated as being adequate, good, or excellent quality of subtraction images by employing a subjective evaluation method, was improved from 73% to 91% by use of the three key techniques. The contralateral subtraction technique can be used for detection of any asymmetric abnormalities, such as lung nodules, pneumothorax, pneumonia, and emphysema, on a single chest radiograph, and therefore has potential utility in a high proportion of abnormal cases.

Biophysical Phenomena↗

PubMed2000

Prevalence of mitochondrial gene mutations among hearing impaired patients.

The frequency of three mitochondrial point mutations, 1555A-->G, 3243A-->G, and 7445A-->G, known to be associated with hearing impairment, was examined using restriction fragment length polymorphism (RFLP) analysis in two Japanese groups: (1) 319 unrelated SNHL outpatients (including 21 with aminoglycoside antibiotic injection history), and (2) 140 cochlear implantation patients (including 22 with aminoglycoside induced hearing loss). Approximately 3% of the outpatients and 10% of the cochlear implantation patients had the 1555A-->G mutation. The frequency was higher in the patients with a history of aminoglycoside injection (outpatient group 33%, cochlear implantation group 59%). One outpatient (0.314%) had the 3243A-->G mutation, but no outpatients had the 7445A-->G mutation and neither were found in the cochlear implantation group. The significance of the 1555A-->G mutation, the most prevalent mitochondrial mutation found in this study of a hearing impaired population in Japan, among subjects with specific backgrounds, such as aminoglycoside induced hearing loss, is evident.

Aminoglycosides↗

PubMed2000

Computerized analysis of the likelihood of malignancy in solitary pulmonary nodules with use of artificial neural networks.

PURPOSE: To develop a computer-aided diagnostic scheme by using an artificial neural network (ANN) to assist radiologists in the distinction of benign and malignant pulmonary nodules. MATERIALS AND METHODS: Fifty-six chest radiographs of 34 primary lung cancers and 22 benign nodules were digitized with a 0.175-mm pixel size and a 10-bit gray scale. Eight subjective image features were evaluated and recorded by radiologists in each case. A computerized method was developed to extract objective features that could be correlated with the subjective features. An ANN was used to distinguish benign from malignant nodules on the basis of subjective or objective features. The performance of the ANN was compared with that of the radiologists by means of receiver operating characteristic (ROC) analysis. RESULTS: Performance of the ANN was considerably greater with objective features (area under the ROC curve, Az = 0.854) than with subjective features (Az = 0.761). Performance of the ANN was also greater than that of the radiologists (Az = 0.752). CONCLUSION: The computerized scheme has the potential to improve the diagnostic accuracy of radiologists in the distinction of benign and malignant solitary pulmonary nodules.

Adult↗

PubMed2000

Improved cardiac contractile functions in hypoxia-reoxygenation in rats treated with low concentration Co(2+).

An intracellular mechanism that senses decreases in tissue oxygen level and stimulates hypoxia-related gene expression has been reported in various cell types including the cardiac cell. The mechanism can also be activated by Co(2+) in normoxia. Thus we investigated the effects of prior chronic oral CoCl(2) on mechanical functions of isolated, perfused rat hearts in hypoxia-reoxygenation. In normoxic rats, 43 days of Co(2+) administration increased hematocrit from 45 +/- 0.3% (control, n = 18) to 51 +/- 0.6% (n = 19). In hypoxia and reoxygenation, Co(2+)-pretreated hearts exhibited a significantly higher rate-pressure product (267 and 163%, respectively) and coronary flow (127 and 118%, respectively) and lower end-diastolic pressure (72 and 60%, respectively) compared with the control hearts. Although the oral Co(2+) administration significantly raised myocardial Co(2+) concentration, it did not affect mitochondrial respiration, tissue glycogen concentration, or myocardial tissue histology. The levels of vascular endothelial growth factor, aldolase-A, and glucose transporter-1 mRNA were significantly elevated in the Co(2+)-treated myocardium. We conclude that cardiac contractile functions would gain hypoxic tolerance when the endogenous cellular oxygen-sensing mechanism is activated.

Adaptation, Physiological↗

PubMed2000

Mulberry leaf extract inhibits the oxidative modification of rabbit and human low density lipoprotein.

In a previous study, we demonstrated that the intake of mulberry leaves or their 1-butanol extract (MLBE) reduced the concentration of serum lipids and atheromatous thickening of arterial intima in hypercholesterolemic rabbits. In the present study, we investigated the antioxidative activity of MLBE and isoquercitrin, the main component of MLBE. First, we determined the effect on a stable radical agent, finding that quercetin, isoquercitrin and MLBE scavenged the DPPH radical. We then determined the copper-induced oxidative modification of rabbit and human low-density lipoprotein (LDL). Oxidation of LDL was spectrophotometrically monitored by changes in absorbance at 234 nm accompanied by the formation of conjugated dienes, and measured the formation of thiobarbituric acid reacting substances (TBARS). Quercetin, an aglycone of isoquercitrin, inhibited the formation of conjugated dienes and TBARS by copper-induced oxidative modification of rabbit and human LDLs. MLBE and isoquercitrin also inhibited the oxidation of LDL. These results indicate that mulberry leaves inhibit the oxidative modification of LDL and suggest that mulberry leaves may had prevent atherosclerosis.

Animals↗

PubMed2000

Characterization of a phage resistance plasmid, pLKS, of silage-making Lactobacillus plantarum NGRI0101.

Phage contamination has resulted in abnormal fermentation in silage. We isolated a phage-resistant strain, Lactobacillus plantarum NGRI0101 from silage. The strain carried two plasmids, pLKL (6.8 kb) and pLKS (2.0 kb). By curing and retransformation of the plasmids, we clarified that pLKS has phage resistant activity, characterized as no adsorption inhibition. pLKS has 2,025 bp and three orfs, orfl23, orf132, and orf918. The predicted amino acid sequence of the orf918 product showed high similarity to those of Rep proteins of Pediococcus halophilus plasmid pUCL287 and Lactobacillus acidophilus plasmid pLA103. The replication origin (ori) was upstream from orf918. There was no gene similar to typical phage resistant genes encoded by known plasmids. The phage resistance of L. plantarum NGRI0101 may possibly be due to a plasmid-encoded abortive infection.

Amino Acid Sequence↗

PubMed2000

Regional variations in the distribution of small intestinal intraepithelial lymphocytes in three inbred strains of mice.

The regional variation in the intraepithelial lymphocytes (IELs) in the small intestine was examined in BALB/c male and female mice and C3H/He and C57BL/6 male mice. The small intestines were taken from 11 to 12-week-old mice and divided equally into 3 parts (the proximal, middle and distal parts). IELs were isolated from each part of the intestine and analyzed with flow cytometer. The number of IELs was highest in the proximal part and lowest in the distal part. The distribution of IEL subsets was markedly different between the proximal and the distal parts, and that in the middle part showed the intermediate pattern. The percentage of alphabeta T cells were higher in the distal part. In alphabeta T cell subset, the percentage of CD8alphaalpha T cells was higher in the proximal part, whereas those of CD4 and CD4CD8alphaalpha double positive T cells were higher in the distal part. In gammadelta T cell subset, no regional variations were found. The regional variations in the number and subsets of IELs showed almost the same patterns between male and female BALB/c mice and similar patterns among three strains of mice. This strongly suggests that the regional variations in the small intestinal IELs are common to mouse species.

Animals↗

PubMed2000

Cellular proliferative and telomerase activity in canine mammary gland tumors.

In canine mammary tumors, we examined the telomerase activity, proliferative activity by proliferative cell nuclear antigen (PCNA) immunohistochemistry, and percentage of apoptotic cells by the deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) method. The relationship between these measures and histopathologic malignancy was also investigated. PCNA index was highest in malignant tumors (adenocarcinoma: 27.0%; malignant mixed tumor: 15.7%), followed by benign tumors (adenoma: 4.4%; benign mixed tumor: 5.3%), hyperplasia (2.1%), and normal mammary gland (0.9%). In adenoma and adenocarcinoma, papillary and solid types showing higher cellularity tended to have higher PCNA indices than did cystic and tubular types. Although the TUNEL index was <1% in all cases, the relationship between this measure and histopathologic diagnosis showed the same tendency as observed in PCNA immunostaining. Telomerase activity was detectable in all adenomas, benign mixed tumors, and adenocarcinomas examined. In contrast, all normal mammary glands, hyperplasias, and malignant mixed tumors were negative for telomerase. Relative telomerase activity (RTA) of adenocarcinoma (56.5) was significantly higher than that of adenoma (27.8) and benign mixed tumor (33.9), and a significant positive correlation (P < 0.001) was noted between RTA and PCNA index. No significant correlations were noted between either PCNA or TUNEL index and clinical features such as metastasis and tumor diameter. PCNA index and telomerase activity may be useful markers for judging malignancy of canine mammary tumors.

Adenocarcinoma↗