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Biomedical subjects

Y Morimoto

Publications and source records attributed to Y Morimoto.

At least 37 records · Page 2Linked to original sources
PubMed2004

Radiographic examination of the mandibular (glenoid) fossa in ancient and modern man.

OBJECTIVE: To compare the morphology of the mandibular (glenoid) fossa between ancient and modern Japanese. METHODS: There were 221 specimens from the ancient period and 206 specimens from the modern period. Radiographs of the mandibular fossa were obtained using a modified Schuller technique and were studied. The length, depth, and area of the mandibular fossa and angulation of the frontal slope of the mandibular fossa on the radiographs were automatically computed. In addition, morphological changes of the mandibular fossa in the ancient or modern periods on radiographs were evaluated in order to assess tendency of temporomandibular joint disorder (TMD). RESULT: The ratio of mandibular fossa having morphological alternation in the modern period was greater than that in the Yayoi. Differences in the length and area between the right and left sides became progressively larger from the Yayoi to modern periods. The angulation of the anterior slope of the mandibular fossa in the modern period was smaller than that in other periods. CONCLUSION: The morphology of the mandibular fossa was shown to have changed and asymmetry has increased from the Yayoi to modern periods. It can be speculated that this change in morphology of the mandibular fossa in the modern period is the result of an increase of TMD.

Cephalometry↗
PubMed2003

Changes in cerebral oxygenation in children undergoing surgical repair of ventricular septal defects.

There have been few published studies on changes in cerebral oxygenation during paediatric cardiac surgery as measured by conventional near-infrared spectroscopy. We studied changes in cerebral oxygenation in 16 children undergoing surgical repair of ventricular septal defects. Fifteen of the patients showed similar patterns of changes: brain tissue concentrations of oxyhaemoglobin decreased significantly during cardiopulmonary bypass, whereas there was no significant change in brain tissue concentrations of deoxyhaemoglobin. In the remaining patient, who suffered decreased blood flow to the lower body during surgery, the pattern of changes was different to that of the other subjects. This patient suffered postoperative respiratory and renal failure. This study suggests that conventional near-infrared spectroscopy may be useful for clinical monitoring during ventricular septal defect repair.

Analysis of Variance↗
PubMed2003

Roles of nociceptin/orphanin FQ and nociceptin/orphanin FQ peptide receptor in respiratory rhythm generation in the medulla oblongata: an in vitro study.

BACKGROUND: Nociceptin/orphanin FQ (N/OFQ) is the endogenous agonist of the orphan opioid receptor-like receptor (NOP receptor, previously termed ORL1), a novel member of the opioid receptor family. The aim of the present study, using in vitro newborn rat preparations, was to elucidate the roles N/OFQ and the NOP receptor play in medullary generation of respiratory rhythm. METHODS: The brainstem-spinal cord from 3-day-old Wistar rats was isolated and perfused with artificial cerebrospinal fluid (27.5 degrees C) equilibrated with oxygen 95% and carbon dioxide 5% at pH 7.4. Respiratory activity was recorded from the C4/C5 ventral roots. The effects of N/OFQ (10 nM, 30 nM, 100 nM) on respiratory frequency (fR) (bursts min(-1)) was measured. Drugs were administered through the recording chamber by means of a perfusion system. In addition, the effects of pretreatment with the classical non-selective opioid receptor antagonist naloxone 1 microM, and the selective NOP antagonist CompB 10 microM, were evaluated. Statistical significance was evaluated using ANOVA followed by Dunnett's test (P<0.05). RESULTS: N/OFQ reduced fR in a concentration-dependent manner. Pretreatment with CompB 10 microM prevented the N/OFQ 10 nM-induced fR reduction, whereas CompB itself was inactive. Pretreatment with naloxone did not prevent the N/OFQ-induced fR reduction. CONCLUSION: N/OFQ acts as a neuromodulator to reduce fR in the respiratory rhythm- generating centre of the medulla oblongata, and this action of N/OFQ is mediated by NOP receptors.

Animals↗
PubMed2003

Evaluation of coronal CT findings of rare cases of isolated medial orbital wall blow-out fractures.

OBJECTIVES: To report rare cases of isolated medial orbital wall blow-out fractures and to evaluate their coronal CT findings. METHODS: Nine cases of medial orbital wall blow-out fractures, diagnosed by coronal CT in a general medical hospital between 1995 and 1999, were studied. CT was performed using direct coronal acquisition with a slice thickness of 5 mm. Images were obtained at bone window settings. Clinical examination findings from the medical records were used to give information on the cause of injury, ocular symptoms and the days after injury that the CT examination was performed. RESULTS: Most of the patients (67%) were young male adults. The cause of injury was most frequently the result of fist fighting or athletics (78%). Diplopia and/or limitation of the gaze were the main ocular symptoms (78%). The average time from injury to CT examination was 4 days (range 0-16 days). Seven of the nine patients with medial orbital wall fractures had isolated medial orbital wall blow-out fractures. Herniation of orbital contents toward the ethmoid sinus was observed among all nine fractures. Only three patients (33%) had a swelling and/or medial deviation of the medial rectus muscle, all three having isolated medial orbital wall blow-out fractures. CONCLUSIONS: Nine cases of medial orbital wall blow-out fractures were examined, seven of which were isolated medial wall blow-out fractures. CT findings of this type of fracture included herniation of the orbital contents toward the ethmoid sinus. However, swelling and/or medial deviation of the medial rectus muscle was also seen.

Adolescent↗
PubMed2003

Effects of epinephrine and phosphodiesterase III inhibitors on bupivacaine-induced myocardial depression in guinea-pig papillary muscle.

BACKGROUND: This study was designed to investigate the effects of epinephrine and the phosphodiesterase III inhibitors amrinone and milrinone on bupivacaine-induced myocardial depression in guinea-pig papillary muscles using an electrophysiological method. METHODS: Electrophysiological studies of the effects of bupivacaine, epinephrine, amrinone and milrinone in normal and high K(+) Tyrode's solution were measured with guinea-pig papillary muscles. Specifically, epinephrine, amrinone and milrinone reversal of bupivacaine-induced depression was measured. RESULTS: Bupivacaine reduced the action potential duration (APD), the maximum rate of rise of the AP (V(max)) and contractile force. Although epinephrine increased the contractile force similarly to amrinone and milrinone, it shortened the APD at 50% repolarization (APD(50)) and 90% repolarization (APD(90)). A high concentration of amrinone shortened APD, while milrinone did not affect APD except for a prolongation of APD(20). In high K(+) Tyrode's solution (25 mM), epinephrine, amrinone and milrinone increased the APD and the contractile force. Epinephrine reversed bupivacaine depression of APD and contractile force to control levels. Amrinone and milrinone restored not only the contractile force but also APD. There was an incomplete recovery of APD(50) for amrinone and the prolongation of APD(20) for milrinone. CONCLUSIONS: Our results suggest that bupivacaine decreases the Ca(+) current (I(Ca)) and Na(+) current (I(Na)). Epinephrine and amrinone may increase I(Ca) and the delayed outward current (I(k)), whereas milrinone may increase I(Ca). The profound cardiovascular depression caused by bupivacaine was effectively reversed by amrinone and milrinone in a manner similar to epinephrine.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2002

The analysis of the usefulness of laparoscopic microwave coagulation therapy for hepatocellular carcinoma in patients with poor hepatic reserve by serial measurements of IL-6, cytokine antagonists, and C-reactive protein.

BACKGROUND: Little is known about the effectiveness of laparoscopic microwave coagulation therapy (L-MCT) for hepatocellular carcinoma (HCC) in patients with liver cirrhosis and poor hepatic reserve. Here, we analyzed the usefulness of laparoscopic MCT by comparing the serum levels of IL-6, cytokine antagonists, and C-reactive protein (CRP) following L-MCT with those following MCT with the open method (O-MCT). METHODS: Sixteen patients with hepatocellular carcinoma (HCC) were separated into L-MCT and O-MCT groups according to ICGR15 (ICGR15 30%<:L-MCT, 30%> :O-MCT). Nine patients with poorer hepatic reserve received L-MCT, while seven patients with relatively good hepatic reserve received O-MCT. Serum levels of cytokine antagonists (interleukin-6, IL-6; interleukin-1 receptor antagonist, IL-1ra; soluble tumor necrosis factor receptor type I, sTNF-R55) and C-reactive protein (CRP) were simultaneously measured on serial postoperative days (POD) by immunoassay. RESULTS: Postoperative serum levels of IL-6, IL-1ra, and CRP were significantly elevated on POD-1 and returned to the preoperative levels on POD-7 in both L-MCT and O-MCT groups. In contrast, no significant elevation of sTNF-R55 was found during the period in both groups. In addition, no statistical differences were found in the levels of IL-6, IL-1ra, sTNF-R, and CRP between the groups, except that the level of IL-6 on POD-1 in L-MCT group was significantly lower than that in the O-MCT group. CONCLUSION: These results suggested that the surgical stress by L-MCT in patients with poorer hepatic reserve were almost equal to that by O-MCT in patients with relatively good hepatic reserve, indicating the usefulness of L-MCT for HCC patients with poorer hepatic reserve. We recommend the laparoscopic approach for future patients with the criterion that ICGR15 is over 30%.

C-Reactive Protein↗
PubMed2002

Critical parameters in the cytotoxicity of photodynamic therapy using a pulsed laser.

Photodynamic therapy (PDT) using a pulsed laser is becoming popular, but its cytotoxic effect is still not clear. We therefore studied the cytotoxicity of PDT using a pulsed laser by changing its irradiation parameters and compared the degrees of cytotoxicity with those of PDT using continuous-wave (CW) light sources. Mice renal cell carcinoma cells were incubated with PAD-S31, a water-soluble photosensitiser of which the excitation peak is 670 nm, and were then irradiated with either a tungsten lamp, a CW diode laser, or a nanosecond pulsed Nd:YAG laser-based optical parametric oscillator system. When the PAD-S31 concentration and total light dose were constant (12 micro g/ml and 40 J/cm(2), respectively), the CW laser caused fluence rate-dependent decrease in cellular proliferation until the fluence rate reached 90 mW/cm(2), at which point inhibition of cellular proliferation was more than 80%. The cytotoxicity then became almost saturated at fluence rates of>90 mW/cm(2). On the other hand, inhibition of cellular proliferation in samples irradiated with the pulsed laser reached 80% even at the fluence rate of 15 mW/cm(2), and, interestingly, the cytotoxicity paradoxically decreased with increase in the fluence rate. Moreover, the cytotoxicity in the PDT using the pulsed laser depended on the repetition rate. The inhibition of cellular proliferation by PDT using 30-Hz irradiation was greater than that by PDT using 5-Hz irradiation when the same fluence rates were used. These results suggest that the efficacy of PDT using a pulsed laser depends considerably on fluence rate and repetition rate.

Animals↗
PubMed2002

Virtual endoscopic view of salivary gland ducts using MR sialography data from three dimension fast asymmetric spin-echo (3D-FASE) sequences: a preliminary study.

OBJECTIVES: We performed magnetic resonance (MR) sialography of parotid gland and/or submandibular gland ducts using three-dimensional fast asymmetric spin-echo (3D-FASE) sequencing. The objective was to make three-dimensional (3D) reconstruction images and virtual endoscopic views of the parotid gland ducts using MR sialography data sets of 3D-FASE sequences. METHODS: We reviewed the MR sialography data sets with 3D-FASE sequencing of 10 control volunteers and six patients. Three-dimensional reconstruction images and virtual endoscopic views of the parotid gland and/or submandibular gland ducts were generated with maximum intensity projection (MIP), shaded surface display (SSD), and volume rendering techniques (VRT). RESULTS: The main parotid gland and/or submandibular gland ducts, large branches within the glands, and small branches were fairly well defined in a very short acquisition time on MR sialographic images with 3D-FASE sequencing in nine of the 10 healthy volunteers. The 3D-reconstruction images of the parotid gland ducts and/or submandibular gland ducts showed the entire length of the branch paths and complete images from all angles, and the virtual endoscopic views showed the endoluminal tracts of the main ducts and the large branches in nine. In the patient with Sjogren's syndrome, chronic sialoadenitis, and salivary calculi in the Wharton ducts, the MR sialographic images showed diffuse areas of punctate high signal intensity, dilatation of Stensen's duct, or stones of Wharton's duct, respectively. Furthermore, the 3D-reconstruction images of the salivary gland ducts showed the stenoses and stones in the branch paths and complete images from all angles, and the virtual endoscopic views showed the stenoses and stones in the endoluminal tracts of the main and large branches. CONCLUSIONS: Our initial experience showed that virtual MR endoscopy could be performed to observe the endoluminal tracts of parotid and submandibular glands. The clinical use of the virtual MR endoscopy for salivary gland ducts has not been established yet. Future applications of the 3D-reconstruction images and virtual endoscopic views using MR sialography data sets of 3D-FASE sequences are very attractive and further expansion of this field is expected.

Adolescent↗
PubMed2002

Utility of frequency-selective fat saturation T2-weighted MR images for the detection of joint effusion in the temporomandibular joint.

OBJECTIVES: To evaluate joint effusion in the temporomandibular joint (TMJ) using frequency-selective fat saturation (FS) T2-weighted images and assess this technique. To investigate whether bone marrow abnormalities and magnetic resonance imaging (MRI) findings of internal derangement may be linked to joint effusion in the TMJ in patients with pain. METHODS: TMJ effusion was sought on FS T2-weighted images and conventional T2-weighted images in 400 joints from 200 patients with TMJ-related pain. Self-reported pain records were obtained from patients immediately before MRI and images assessed by the amount of TMJ fluid graded bilaterally using reference films by two radiologists. Other parameters recorded included disk displacement categories and condyle marrow abnormalities. The association between the recorded parameters and TMJ effusion judged by FS-sequences or conventional sequences was analysed using chi-square and Kappa tests. RESULTS: The detection rate of TMJ effusion by FS-sequences was significantly greater than by conventional methods, and the results showed a significant relationship between MRI interpretation of TMJ effusion using FS-sequences or conventional methods and the presence of pain. The correlation between TMJ effusion on FS-sequences and pain was significantly stronger than the conventional method. Kappa test indicated good agreement between pain and MRI TMJ effusion by FS-sequences (kappa = 0.66), but not by conventional sequences (kappa = 0.56). The other parameters showed a similar trend for TMJ-related pain. CONCLUSIONS: FS T2-weighted imaging is useful for detection of TMJ effusion, without known causes and confirms the importance of TMJ effusion as an indicator in patients with TMJ-related pain, bone abnormalities, and disk displacement.

Adipose Tissue↗
PubMed2002

Population-based genetic alterations in Ewing's tumors from Japanese and European Caucasian patients.

BACKGROUND: The incidence of Ewing's tumors (ETs) is lower in Asians or African-Americans than in Caucasians. PATIENTS AND METHODS: Japanese ETs were available for analysis of chromosomal aberrations by comparative genomic hybridization (n = 16) and for expression of chimeric EWS transcripts by reverse-transcriptase polymerase chain reaction (n = 11). These results in Japanese patients were compared with those of 62 ETs in European Caucasian patients registered in the European Intergroup Cooperative Ewing's Sarcoma Study. RESULTS: Japanese patients with ET had lower overall survival (P = 0.0446) and relapse-free survival (P = 0.0371) compared with European Caucasian patients. Ten of 11 Japanese ETs and 31 of 62 European Caucasian ETs had type I (EWS exon 7 to FLI1 exon 6) fusion transcripts. In Japanese ETs, the median numbers of chromosomal aberrations were 2.0 and 6.0 in 11 primary tumors and five relapsed tumors, respectively. In European Caucasian ETs, the median number of changes were 2.5 and 5.0 in 52 primary and 10 relapsed tumors, respectively. Frequent gains were 8q (38%), 8p (31%) and 12q (25%) in Japanese ETs and 8q (52%), 8p (48%) and 12q (19%) in European Caucasian ETs. Frequent losses were 19q (44%), 19p (38%) and 17p (25%) in Japanese ETs and 16q (21%), 19q (18%) and 17p (15%) in European Caucasian ETs. The incidence of losses of 19p (P = 0.0215) and 19q (P = 0.0277) were significantly higher in Japanese ETs than in European Caucasian ETs. An amplification (1p33-p34) was observed in only one Japanese ET. CONCLUSIONS: Japanese patients with ET in this study had a worse prognosis than European Caucasian patients. In molecular genetic analyses, Japanese ETs had a higher frequency of loss of chromosome 19 than European Caucasian ETs. Different genetic aberrations may explain the different incidences and prognoses of ET between Caucasian and Japanese patients.

Adolescent↗
PubMed2002

Effects of mild and moderate hypothermia on apoptosis in neuronal PC12 cells.

BACKGROUND: There is still a possibility that mild hypothermic therapy may be useful as a neuroprotective tool during the intraoperative period, although the mechanism of cerebral protection by mild hypothermia is not well understood. We hypothesized that mild hypothermia may be protective against cerebral ischaemia by inhibiting post-ischaemia apoptosis. In this study, we used serum-deprived PC12 cells as the neuronal apoptotic model and examined the direct effects of mild and moderate hypothermia. METHODS: Apoptosis was induced by depriving the cell culture medium of serum, which is one of the most representative methods to induce apoptosis, but not necrosis, in PC12 cells. Effects of mild (35 and 33 degrees C) and moderate (31 and 29 degrees C) hypothermia on apoptosis were evaluated. Cytotoxicity (lactate dehydrogenase leakage) and the percentage of apoptotic cells (calculated by flow cytometry with propidium iodide) were evaluated 4 days after induction of apoptosis. As a control, cells without induction of apoptosis were incubated under the same conditions as the apoptosis group. RESULTS: Without induction at 37 degrees C, cytotoxicity and the percentage of apoptotic cells were over 60 and 90%, respectively. At each temperature examined below 35 degrees C, significant decreases in cytotoxicity and the percentage of apoptotic cells were observed. Mean cytotoxicity at 31 and 29 degrees C was 50.2 (SD 4.2)% and 47.9 (4.4)%, respectively. The percentage of apoptotic cells at 31 and 29 degrees C was 42.5 (7.4)% and 36.5 (7.3)%, respectively. In the control group, cytotoxicity and the percentage of apoptotic cells were significantly higher at 29 degrees C than at 37 degrees C. CONCLUSIONS: Mild and moderate hypothermia (29-35 degrees C) inhibited apoptosis, although hypothermia below 30 degrees C may induce apoptosis in intact cells.

Animals↗
PubMed2001

Systematic elucidation of effects of tranexamic acid on fibrinolysis and bleeding during and after cardiopulmonary bypass surgery.

The aim of this study was to systematically elucidate the effects of tranexamic acid on fibrinolysis and bleeding during and after cardiopulmonary bypass (CPB) surgery. Twenty-two patients undergoing CPB surgery were randomized to receive 100 mg/kg tranexamic acid or an equal volume of saline after anesthesia induction and prior to skin incision. Plasma levels of tissue plasminogen activator (t-PA) antigen and activity, crosslinked fibrin degradation products (D-dimer), alpha2-antiplasmin-plasmin complex, and plasminogen activator inhibitor-1 (PAI-1) antigen were measured. Blood samples were obtained after induction of anesthesia, before, during, and after CPB, at the end of surgery, and the next morning after surgery. Intraoperative and postoperative blood loss during 24 h after surgery was recorded. Patients' demographics were similar between the two groups. No patients suffered from thrombotic complications after surgery. In the tranexamic acid group, fibrinolytic activity and secondary fibrinolysis as measured by t-PA activity and D-dimer were markedly suppressed during CPB surgery (P=.042 and P=.015, respectively). Decreased fibrinolytic activity and fibrinolysis were accompanied by reduction of perioperative bleeding in the tranexamic acid group. We could also find a good positive correlation between the peak levels of t-PA activity and D-dimer (r(2)=.4203, P=.0011). No differences in the t-PA antigen, PAI-1 antigen release, and plasmin inhibition by alpha2-antiplasmin were apparent between the two groups. In a randomized, prospective trial of patients undergoing CPB surgery, we demonstrated that the synthetic antifibrinolytic drug tranexamic acid effectively suppresses fibrinolysis by inhibiting t-PA and plasmin activity with clear reduction of perioperative blood loss. While tranexamic acid had no effects on the other important fibrinolytic inhibitors like PAI-1 and alpha2-antiplasmin.

Antifibrinolytic Agents↗
PubMed2001

Radical production simulated by photoirradiation of the diol dehydratase-adeninylpentylcobalamin complex.

In the course of structural studies of diol dehydratase-cobalamin complexes, it was found that the electron density corresponding to the cyano group of the enzyme-bound cyanocobalamin is almost not observable at room temperature and very low even at cryogenic temperatures, suggesting its dissociation from the Co atom upon X-ray irradiation. On the contrary, the adenine moiety of the enzyme-bound adeninylpentylcobalamin was clearly located in the electron density map. When the enzyme-adeninylpentylcobalamin complex was illuminated with visible light, the electron density between the C5' and Co atoms disappeared, and the temperature factors of the atoms comprising the pentamethylene group became much larger than those in the dark. This indicates a Co-C bond cleavage and that the adenine moiety remains held by hydrogen bonds with some residues in the enzyme. Thus, the formation of an adenine-anchored radical upon illumination was demonstrated crystallographically with this complex. These observations clearly indicate that homolysis of the Co-C bond of alkylcobalamin takes place upon illumination with visible light but is not readily cleaved during X-ray irradiation.

Crystallography, X-Ray↗
PubMed2001

Stereocontrolled total synthesis of the Stemona alkaloid (-)-stenine.

The Stemona alkaloid stenine (1), isolated from Stemona tuberosa of physiologically active stemonaceous plants, possesses the structurally novel and unique azepinoindole skeleton (B,C,D-ring system). We have achieved the asymmetric total synthesis of (-)-stenine (1), starting from 1,5-pentanediol (10). The key features are an intramolecular diastereoselective Diels-Alder reaction of the (E,E,E) triene 6, prepared in a convergent fashion from three components--dienyl chloride 7, dithiane 8, and chiral phosphonate 9--and efficient construction of the tricyclic A,B,D-ring system 29 through thermodynamically controlled regioselective enolization of the bicyclic ketone 25. In this article, we describe in detail the highly stereocontrolled total synthesis of (-)-stenine (1). These results should be useful for the asymmetric total synthesis of another, more complex. molecule: tuberostemonine (2), the synthesis of which has never been reported.

Alkaloids↗