Biomedical subjects

H Yamamoto

Publications and source records attributed to H Yamamoto.

At least 127 records · Page 7Linked to original sources

PubMed2003

Successful en-bloc resection of large superficial tumors in the stomach and colon using sodium hyaluronate and small-caliber-tip transparent hood.

En-bloc resection is desirable for accurate histopathological assessment of tissue specimens obtained using endoscopic mucosal resection (EMR). A new EMR method using sodium hyaluronate and a small-caliber-tip transparent hood has been developed. This is a peeling-off method using a needle-knife for mucosal and submucosal incisions. Long-lasting submucosal thickening resulting from an injection of sodium hyaluronate, and good visualization of the submucosal tissue with the aid of a small-caliber-tip transparent hood, make the cutting procedures easy and safe. A large superficial gastric cancer and a large villous tumor of the sigmoid colon were endoscopically resected using this method. En-bloc endoscopic resection was successful in both patients. The gastric lesion was an well-differentiated intramucosal adenocarcinoma, completely resected in a specimen measuring 97 x 50 mm. The colonic lesion was an intramucosal well-differentiated adenocarcinoma in adenoma, completely resected in a specimen measuring 70 x 55 mm in diameter. No significant complications were noted in either patient. The new method of EMR using sodium hyaluronate and the small-caliber-tip transparent hood is a promising method for endoscopic en-bloc resection of large superficial neoplastic lesions, both in the stomach and the colon.

Adenocarcinoma↗

PubMed2003

Double-balloon enteroscopy: preliminary experience in patients with obscure gastrointestinal bleeding or chronic abdominal pain.

BACKGROUND AND STUDY AIMS: Even in the era of capsule endoscopy, diseases of the small bowel are sometimes difficult to diagnose, and endoscopic treatment is not possible without surgical laparotomy. The new method of carrying out enteroscopy using a double-balloon technique allows not only diagnostic but also therapeutic endoscopic interventions for lesions in the small bowel. Preliminary experience with this new method is reported here. PATIENTS AND METHODS: Between the end of March 2003 and August 2003, eight patients (four women, four men; mean age 59 +/- 23 years, range 20 - 90) with chronic gastrointestinal bleeding or abdominal pain, or both, underwent enteroscopy using the double-balloon technique. Seven of the patients had been suffering from chronic gastrointestinal bleeding for 56 +/- 49 months (range 3 - 120 months, median 48 months). The lowest hemoglobin levels ranged from 3.6 g/dl to 8.6 g/dl (mean 6.7 +/- 1.7 g/dl), and a mean of 7.6 +/- 5.6 (range 1 - 15) blood units had been transfused. Capsule endoscopy was carried out in six patients, revealing angiodysplasias in three, suspected Crohn's disease in one, fresh blood in the small bowel without a lesion in one, and a focal enanthema in another patient. RESULTS: Enteroscopy with the double-balloon technique was carried out using the oral approach in all patients and additionally with the anal approach in four patients. In two patients with multiple angiodysplasias, it was possible to examine the whole small bowel and to treat the angiodysplasias. All of the capsule endoscopy findings were confirmed; a definite bleeding source was found and treated in two patients with unclear bleeding, and in another patient the real bleeding source was found (not angiodysplasia). The enteroscopy system was easy to handle in all cases. No complications occurred. It was possible to carry out the procedure with the patients under sedoanalgesia. CONCLUSIONS: This new enteroscopy system is easy to handle and seems to be safe. Visualization of the whole small bowel is possible using both the oral and anal approaches. Enteroscopy with the double-balloon technique promises to become a standard method for diagnostic and therapeutic endoscopy of the small bowel without surgical laparotomy.

Abdominal Pain↗

PubMed2003

Detection of cerebral hypoperfusion with bispectral index during paediatric cardiac surgery.

BACKGROUND: The bispectral index (BIS) may indicate changes in cerebral activity when the cerebral circulation is affected by acute hypotension. METHODS: We measured BIS and cerebral haemoglobin saturation (Sr(O(2))) by near-infrared spectroscopy in 10 children undergoing cardiac surgery. RESULTS: We noted 14 episodes of simultaneous decreases in Sr(O(2)) and BIS during acute hypotension in five children. An acute decrease in BIS, which coincided with a decrease in Sr(O(2)) suggesting a reduction in cerebral blood flow, was associated with acute slowing of the raw EEG waveforms. CONCLUSIONS: Our findings suggest that an acute decrease in BIS during acute hypotension indicates cerebral hypoperfusion, and that cerebral hypoperfusion caused by hypotension may occur frequently during paediatric cardiac surgery.

Blood Pressure↗

PubMed2003

The fate of estrogenic compounds in the aquatic environment: sorption onto organic colloids.

In this study, sorption of some estrogens and estrogenic compounds onto several organic colloids was examined using fluorescence quenching techniques. Selected organic colloids included humic substances of several sources, Aldrich humic acid (AHA), Suwannee River humic acid (SRHA), Suwannee River fulvic acid (SRFA), and Nordic fulvic acid (NFA). Polysaccharides, alginic acid (AA) and dextran (Dex), and tannic acid (TA) were also selected. 17beta-estradiol (E2), 17alpha-ethynylestradiol (EES), and estriol (E3) were selected as estrogens. Nonylphenol (NP), octylphenol (OP), and dibutylphthalate (DBP) were selected as estrogenic compounds. For most of the selected compounds, the sorption coefficients were in the order of TA > humic acids (SRHA or AHA) > fulvic acids (NFA or SRFA) > AA. The smallest or no significant sorption onto dextran was found for selected estrogens and estrogenic compounds. Comparing those compounds, neither a significant trend nor linear correlation with Log K(ow) was found. The resulting sorption coefficients for humic substances and TA suggested approximately 15 to 50% of the estrogens and estrogenic compounds were bound in typical natural water of 5 mg TOC/L and significant effects on the removal of them by water treatment processes, toxicity, or bioavailability were suggested.

Adsorption↗

PubMed2002

Ultrasonographic evaluation of congenital dislocation of the knee.

The authors describe ultrasonographic findings in a newborn girl with congenital dislocation of the knee (CDK). Ultrasonography showed a hyperechoic area and focal narrowing of the distal quadriceps as compared to the unaffected contralateral side, indicating the presence of fibrosis, which is the main pathologic feature of congenital dislocation of the knee. The hyperechoic area decreased after reduction of the dislocation and with patient growth. Ultrasonography was useful in evaluating CDK because it provided a direct view of the pathologic lesion, was painless, and did not involve exposure to X-rays. Further, we were able to serially evaluate the abnormal findings and provide advice regarding daily activity to the parents of the patient with CDK.

Female↗

PubMed2002

A phase I study of combination chemotherapy with gemcitabine and oral UFT for advanced non-small cell lung cancer.

A phase I study was carried out to determine the optimal dose and administration schedule for combined UFT plus gemcitabine therapy in patients with non-small cell lung cancer. Twenty-four patients (including 11 patients previously treated with cisplatin as the key drug) received oral UFT 400 mg x m(-2) on days 1 to 14 with intravenous infusions of gemcitabine (800 mg x m(-2) on days 8 and 15, or 900 mg x m(-2) on days 8 and 15, or 900 mg x m(-2) on days 1, 8 and 15). The most appropriate dosing option appeared to be 400 mg x m(-2) per day of oral UFT for 14 consecutive days with 900 mg x m(-2) gemcitabine on days 8 and 15. Eight of the 24 patients achieved partial response. The combination chemotherapy UFT and gemcitabine was well tolerated and may benefit patients with advanced non-small cell lung cancer. A multicentre phase II study using a 3-weekly regimen is in progress.

Administration, Oral↗

PubMed2002

Complete nucleotide sequence of the genomic RNA of Aconitum latent virus (genus Carlavirus) isolated from Delphinium sp..

We determined the complete nucleotide sequence of Aconitum latent virus (AcLV-D) isolated from Delphinium sp. The genomic RNA of AcLV-D is 8,657 nucleotides in length, excluding the poly (A) tail. Based on computer analysis, six open reading frames (ORFs) were identified as for other carlaviruses. Although each ORF differs from those of previously reported carlaviruses, the coat protein of AcLV and Potato virus M (PVM) shows a high level of identity. The results suggest that AcLV is a distinct carlavirus species but closely related to PVM.

Amino Acid Sequence↗

PubMed2002

Distribution pattern of versican, link protein and hyaluronic acid in the rat periodontal ligament during experimental tooth movement.

The ability of the periodontal ligament (PDL) to rapidly remodel is the basis of orthodontic tooth movement. During the tooth movement, matrix proteoglycans (PGs) may play important roles in spatial, mechanical and biological aspects for the maintenance and repair of the PDL. The aim of this study was to characterize the distribution of a large hyaluronic acid (HA)-binding proteoglycan, versican, link protein (LP) and HA in the rat molar PDL during experimental tooth movement by histochemical and immunohistochemical methods. Experimental tooth movement was performed according to Waldo's method. Histologically, regressive changes, such as decrease of fibroblasts and collagen fibers and exudative change of edema were observed in the compressive side and progressive changes, such as proliferation of fibroblasts and collagen fibers, in the strain side one day after treatment. By 3 days after tooth movement, regressive or progressive changes were not observed in either side. Using monoclonal antibodies specific to versican core protein or LP, the positive immunoreactivity for both molecules was constantly observed throughout the PDL. After the experimental force was applied to the tooth, however, the immunostainings of versican and LP became significantly intense only in the compressive side but decreased in the strain side. The intensity in the compressive side was strongest one day after the force was applied and gradually diminished thereafter. HA of both sides did not change during experimental tooth movement. Since HA is present in the PDL, large amounts of versican and LP expressed in the compressive side may create large hydrated aggregates via their association with HA that dissipates the compressive force applied to this tissue.

Animals↗

PubMed2002

Adeno-associated virus vector-mediated gene transfer into dystrophin-deficient skeletal muscles evokes enhanced immune response against the transgene product.

Duchenne muscular dystrophy (DMD) is an X-linked, lethal muscular disorder caused by a defect in the DMD gene. AAV vector-mediated micro-dystrophin cDNA transfer is an attractive approach to treatment of DMD. To establish effective gene transfer into skeletal muscle, we examined the transduction efficiency of an AAV vector in skeletal muscles of dystrophin-deficient mdx mice. When an AAV vector encoding the LacZ gene driven by a CMV promoter (AAV-CMVLacZ) was introduced, beta-galactosidase expression markedly decreased in mdx muscle 4 weeks after injection due to immune responses against the transgene product. We also injected AAV-CMVLacZ into skeletal muscles of mini-dystrophin-transgenic mdx mice (CVBA3'), which show ameliorated phenotypes without overt signs of muscle degeneration. AAV vector administration, however, evoked substantial immune responses in CVBA3' muscle. Importantly, AAV vector using muscle-specific MCK promoter also elicited responses in mdx muscle, but at a considerably later period. These results suggested that neo-antigens introduced by AAV vectors could evoke immune reactions in mdx muscle, since increased permeability allowed a leakage of neo-antigens from the dystrophin-deficient sarcolemma of muscle fibers. However, resident antigen-presenting cells, such as myoblasts, myotubes and regenerating immature myofibers, might also play a role in the immune response.

Adenoviridae↗

PubMed2002

Effects of alcohol intake on ambulatory blood pressure, heart rate, and heart rate variability in Japanese men with different ALDH2 genotypes.

The effects of alcohol intake on haemodynamics and heart rate variability were investigated with relation to genotypes of aldehyde dehydrogenase 2 (ALDH2), which were determined in 33 male Japanese volunteers (mean +/- s.e., 35.7 +/- 1.4 years) using the PCR-RFLP method. On the alcohol intake day, they consumed 660 ml of beer containing 33 ml of ethanol (0.3-0.5 g/kg of body weight) from 18.00 to 18.30. On the control day, they ingested the same amount of non-alcoholic beer. Ambulatory blood pressure, heart rate, and ECG R-R intervals were measured during a 24-h period with a portable recorder. A power spectral analysis of R-R intervals was performed to obtain the low-frequency (LF) and high-frequency (HF) components. Sixteen subjects were homozygotes for the normal ALDH gene (active ALDH2), only one was a homozygote for the mutant ALDH2 gene (inactive ALDH2), and the remaining 16 were heterozygotes (inactive ALDH2). Alcohol intake did not change 24-h average blood pressure (BP) either in the active ALDH2 group or in the inactive ALDH2 group. However, during the time interval from 18.30 to 0.00, alcohol intake significantly decreased diastolic BP in the active ALDH2 group and both systolic and diastolic BPs in the inactive ALDH2 group. In the active ALDH2 group, alcohol intake did not change heart rate, while in the inactive ALDH2 group, alcohol intake significantly increased 24-h average heart rate by 5.3 +/- 1.6 beats per minute (P < 0.01). In the active ALDH2 group, neither the LF nor the HF component was changed by alcohol intake, while in the inactive ALDH2 group, both the LF and the HF components were significantly decreased during the time interval from 18.30 to 0.00. These results demonstrate for the first time that ALDH2 genotypes modify the effects of intake of a small amount of alcohol on haemodynamics and heart rate variability in Japanese men.

Adult↗

PubMed2002

Motor evoked potentials elicited from erector spinae muscles in patients with thoracic myelopathy.

STUDY DESIGN: A prospective study was conducted to test the utility of the motor evoked potentials (MEPs) from the erector spinae muscles as a measure to estimate the motor level of thoracic compression myelopathies in 13 consecutive patients. OBJECTIVE: To confirm whether this test is a useful addition to the neurological examination in non-invasively localizing the level responsible for the main functional change in mild to moderate thoracic myelopathy. SETTING: Department of Orthopaedic Surgery, Kochi Medical School, Kochi, Japan. METHODS: This electrophysiological study consisted of transcranial magnetic stimulation (TMS) of the brain and surface recording of MEPs from voluntarily contracted erector spinae muscles with the patient in the prone position. The recordings were obtained unilaterally from the same side as the lower-limb affected at 12 serial interspinous levels from T5-6 to L4-5. The results were compared to the MEP data from normal subjects and to neurological and MRI findings. RESULTS: Multisegmental MEP studies demonstrated a focal conduction block in one patient, a single site of conduction delay in seven, and normal conduction in five. The conduction block was characterized by an abrupt reduction in amplitude of the MEPs. Examination of the sites conduction delay showed that the latency difference between the two adjacent levels was longer than the corresponding normal upper limit by 1.00+/-0.40 ms (range, 0.62-1.61 ms). The site of conduction abnormalities approximated to the compressive lesion site shown by MRI. All five patients with false-negative MEP findings had the lesion site at or caudal to the T10-11 vertebral level. CONCLUSION: This method has the advantage of instantaneously testing multisegments of the thoracic spinal cord. The technique is of particular value in estimating the motor level of the lesions rostral to T10-11 vertebral level, which can not be achieved by clinical examinations or MEP recordings from the lower limb.

Adult↗

PubMed2002

Nerve sheath myxoma of the tongue in a child.

Nerve sheath myxoma (NSM) is a benign peripheral nervous system tumour that rarely occurs in the oral cavity. Among 17 cases of oral NSM described in the literature (average patient age 33 years), only two, including the present case, have been reported in children. The present case occurring in an 8-year-old boy was therefore extremely rare. Histopathologically, the tumour was found as multinodules under the mucosal epithelium, and was composed of spindle- or stellate-shaped cells with a myxoid background that stained with alcian blue and toluidine blue. Immunohistochemically, the tumour cells were strongly positive for S-100 beta protein and neuron-specific enolase. These results suggested that the tumour originated from Schwann cells.

Child↗

PubMed2002

Molecular cloning and characterization of mouse calcitonin gene-related peptide receptor.

The calcitonin gene-related peptide (CGRP) plays important roles as a neurotransmitter/neuromodulator in the central nervous system, and as a potent vasodilator when secreted from peripheral, perivascular nerves through its specific receptors. In this study, we cloned mouse cDNA counterparts of the human CGRP receptor composed of calcitonin receptor-like receptor (CRLR) and receptor activity modifying protein 1 (RAMP1) and examined the signal transduction mechanism through the CGRP receptor. Mouse CRLR (mCRLR) is a 462-amino acid G protein-coupled heptahelical receptor, and mouse RAMP1 (mRAMP1) is a 148-amino acid single membrane-spanning protein with a short cytoplasmic portion. Specific binding of (125)I-CGRP was detected only when both mCRLR and mRAMP1 cDNAs were cotransfected to COS-7 cells, and the Kd value of the receptor was 2.2 x 10(-10) M. CGRP induced a marked elevation of the intracellular cAMP levels in COS-7 cells cotransfected with mCRLR and mRAMP1. CGRP signaling through the mCRLR/mRAMP1 receptor complex was found to increase the promoter activities of cyclic AMP responsive element and serum responsive element in the co-transfected HeLa cells. These results indicate that mCRLR and mRAMP1 constitute a functional mouse CGRP receptor for the transduction of CGRP signaling by PKA and extracellular signal-regulated kinase signal transduction pathways.

Amino Acid Sequence↗

PubMed2002

Origin of the biomechanical properties of wood related to the fine structure of the multi-layered cell wall.

In this study, a basic model is introduced to describe the biomechanical properties of the wood from the viewpoint of the composite structure of its cell wall. First, the mechanical interaction between the cellulose microfibril (CMF) as a bundle framework and the lignin-hemicellulose as a matrix (MT) skeleton in the secondary wall is formulated based on "the two phase approximation." Thereafter, the origins of (1) tree growth stress, (2) shrinkage or swelling anisotropy of the wood, and (3) moisture dependency of the Young's modulus of wood along the grain were simulated using the newly introduced model. Through the model formulation; (1) the behavior of the cellulose microfibril (CMF) and the matrix substance (MT) during cell wall maturation was estimated; (2) the moisture reactivity of each cell wall constituent was investigated; and (3) a realistic model of the fine composite structure of the matured cell wall was proposed. Thus, it is expected that the fine structure and internal property of each cell wall constituent can be estimated through the analyses of the macroscopic behaviors of wood based on the two phase approximation.

Anisotropy↗

PubMed2002

[Aortic arch replacement with covered stent-graft as elephant trunk for a type A acute aortic dissection].

We report a case of aortic arch replacement with a covered stent-graft as an "elephant trunk". A 54-year-old woman was diagnosed with Stanford type A aortic dissection. The initial intimal tear was located in the distal aortic arch. Under deep hypothermic circulatory arrest and retrograde cerebral perfusion, the distal end of the arch graft, which was turned inside out and reinforced with a Z-stent, was inserted into the distal true lumen as an "elephant trunk". Distal anastomosis was performed between the aortic wall and the inverted external graft. Graft replacement of the aortic arch and ascending aorta was followed by proximal arch grafting. Coronary artery bypass grafting to RCA was performed concomitantly. The postoperative course was uneventful, and the distal false lumen became thrombosed. This procedure is effective for reliable distal anastomosis and prevention of blood leakage into the distal false lumen.

Acute Disease↗

PubMed2002

[Long-term results of aortic arch replacement using combination of deep hypothermic circulatory arrest and retrograde cerebral perfusion; comparison of result for atherosclerotic aneurysm and aortic dissection].

Between 1992 and 2001, 73 patients with aortic arch lesion underwent surgical treatment. The aneurysm was characterized by atherosclerosis in 54 patients (TAA) and by aortic dissection in 19 patients (DAA). All patients received graft replacement under combination of deep hypothermic circulatory arrest and retrograde cerebral perfusion. The hospital mortality rate for all patients was 15.6%. The follow-up period of 61 survival patients ranged from 2 to 90 months (mean 33.2 months). The actuarial survival rate was 93.2%, 83.5%, and 79.7% at 1, 3, and 5 years, respectively. No significant difference was noted between TAA and DAA in the actuarial survival rate. The freedom from vascular complication was 97.9%, 95.8%, and 95.8% at 1, 3, and 5 years, respectively. The rate was significant higher in the patients of DAA than in those of TAA (TAA: 100%, 100%, and 100%, DAA: 90.9%, 81.8%, and 81.8%). The freedom from cardiac complication was 96.4%, 89.7%, and 84.1% at 1, 3, and 5 years, respectively. There was no significant difference between TAA and DAA. The freedom from cerebrovascular complication was 100%, 97.6%, and 83.4% at 1, 3, and 5 years, respectively. No significant difference was noted between TAA and DAA. The late result of surgical treatment for the aortic arch using combination of deep hypothermic circulatory arrest and retrograde cerebral perfusion was satisfied. The long-term survival rate was higher in TAA patient than in DAA one. The possibility remained that fatal vascular complication affected the long-term survival rate.

Aged↗

PubMed2002

[Surgical management of acute empyema].

Basic principles apply to the management of all forms of acute empyema: investigation and treatment of the underlying infection, drainage of purulent collection, obliteration of the space, and treatment of the associated intercurrent medical conditions. From July 1999 to May 2001, we performed surgical treatment in 11 patients for acute empyema. There were 4 cases of the fibrinopurulent phase and 7 cases of the organizing phase. Surgical procedure was 7 open thoracotomies and 4 thoracoscopies. The mean operating time was 154.2 +/- 36.6 minutes and blood loss during surgery was 344.7 +/- 274.8 ml. There was no procedure-related morbidity. In conclusion, early aggressive surgical approach is a feasible method for treatment of acute empyema.

Acute Disease↗

PubMed2002

[Calcium signaling and brain functions].

Calcium signaling plays a critical role in various cell types by activation of receptors and Ca2+ channels in response to neurotransmitters, hormones, growth, factors etc. Although a variety of functions of intracellular Ca2+ are reported, Ca2+/calmodulin-dependent protein kinases (CaMK) are involved in their mediation. We have been studying on CaMK I, II, III, IV and K in the dynamic regulation in the cells in relation to functions. In this study, we elucidated the structures of the isoforms of CaMKII subunits with nuclear translocation signal (NTS). NTS is included in the variable domain following the regulatory domain with a sequence of KKRK. The isoforms of CaMK subunits such as alpha B, gamma A, gamma A.B, delta 3 and delta 7 contain NTS in the sequences of the structures. Transfection of the isoforms with NTS into NG108-15 cells stimulated the expression of brain-derived neurotrophic factor in the cytoplasm. Activation of CaMKII and IV and mitogen-activated protein kinase (MAPK) was observed during long-term potentiation (LTP) induction in the CA1 area of hippocampus. The activation of CaMKII was sustained for a long period, whereas that of CaMKIV and MAPK was transient. The results suggest that CaMKII is involved in LTP induction, while CaMKIV and MAPK are rather involved in LTP maintenance. We present and discuss our recent studies on regulation of CaMKs in neuronal functions.

Brain↗