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Biomedical subjects

K Hanaoka

Publications and source records attributed to K Hanaoka.

At least 19 recordsLinked to original sources
PubMed2006

Transient decreases in Bispectral Index without associated changes in the level of consciousness during photic stimulation in an epileptic patient.

This case report describes a patient with a history of epileptic seizures who showed unusual decreases in the Bispectral Index (BIS) attributable to the induction of abnormal slow electroencephalographic (EEG) waves by photic stimulation, without any associated decrease in his level of consciousness. After starting anticonvulsive therapy, photic stimulation no longer induced abnormal EEG activity nor decreased BIS values. These findings suggest that BIS values may not accurately reflect a patient's actual level of consciousness in the presence of epilepsy-related abnormal EEG activity and that the BIS monitor may be able to track such EEG changes.

Adult↗
PubMed2006

Transition of mouse de novo methyltransferases expression from Dnmt3b to Dnmt3a during neural progenitor cell development.

Dnmt3a and Dnmt3b, which are known as functional de novo methyltransferases, are responsible for creating genomic methylation patterns during mammalian development. Recently, we have shown that specific expression of Dnmt3b in epiblast, embryonic ectoderm, hematopoietic progenitor cells and spermatogonia cells is followed by Dnmt3a expression (Watanabe D, Suetake I, Tada T, Tajima S (2002) Stage- and cell-specific expression of Dnmt3a and Dnmt3b during embryogenesis. Mech Dev 118:187-190; Watanabe D, Suetake I, Tajima S, Hanaoka K (2004) Expression of Dnmt3b in mouse hematopoietic progenitor cells and spermatogonia at specific stages. Gene Expr Patterns 5:43-49). In this study, we analyzed the expression of mouse de novo methyltransferases during development of the nervous systems. In the embryonic olfactory epithelium (OE), Dnmt3b was specifically expressed in Mash1 positive globose basal cells (i.e. transiently amplifying neural progenitor cells), while Dnmt3a was expressed in immature olfactory receptor neurons. Dnmt3b-positive cells were rarely observed in the adult OE, but were increased in regenerating OE with intranasal ZnSO(4) administration. Dnmt3b was also detected in the E8.5 neural plate, E10.5 spinal cord and retina cells, while Dnmt3a was expressed in postmitotic young neurons. Furthermore, Dnmt3b was specifically expressed in ES cells, while Dnmt3a was transiently expressed during neural cell differentiation of ES cells. Dnmt3b is specifically expressed in progenitor cells during hematopoiesis, spermatogenesis and neurogenesis, suggesting an important role in the initial steps of progenitor cell differentiation. Dnmt3a is expressed in postmitotic young neurons following the Dnmt3b expression. Dnmt3a may be required for the establishment of tissue-specific methylation patterns of the genome. The coordinated expression of de novo methyltransferases from Dnmt3b to Dnmt3a suggests conserved mechanisms of de novo methylation of the genome and different functions for Dnmt3b and Dnmt3a during progenitor cell development.

Animals↗
PubMed2005

[Anesthesia for thoracic surgery in elderly patients].

Aging and advances in medical technology have lead to a rise in the number of patients of advanced age undergoing surgery. This is also observed in thoracic surgery. Aging itself is not a disease, but it is one of the risk factors of perioperative complications. Individual assessment of patients is required to ascertain the organ system capacity and functional reserve. The management of anesthesia is based on the characteristic changes in the elderly, related to physiology and pharmacokinetics, taking account of possible perioperative complications.

Aged↗
PubMed2004

Usefulness of epidural anesthesia in gynecologic laparoscopic surgery for infertility in comparison to general anesthesia.

BACKGROUND: Although the advantages of epidural anesthesia in open surgery have been established, its usefulness in the setting of laparoscopic surgery remains to be studied. METHODS: Patients undergoing laparoscopic surgery for infertility were randomly administered epidural anesthesia (group A, n = 11) or general anesthesia (group B, n = 9). The operation was performed under 4 mmHg pneumoperitoneum and in the 20 degrees Trendelenburg position. Respiratory function tests using a spirometer and blood gas analysis were performed during the intra- or perioperative period. Pain status was evaluated with visual analog scale scoring. The number of postoperative recovery days needed to resume daily activities was obtained by a questionnaire. RESULTS: Respiratory rate, minute volume, P(a)CO2, % vital capacity (VC), and forced expiratory volume in 1 s (FEV1) % were virtually constant throughout the study period in group A, whereas %VC was decreased immediately after operation in group B (p < 0.05). Minute volume immediately after operation was significantly increased in group B compared with group A (p < 0.01), suggesting shallow respiration in women undergoing general anesthesia. Observed pain scores on abdominal pain, shoulder pain, and dyspnea were very low during operation in group A. Pain scores immediately and 3 h after operation were also minimal in group A, whereas abdominal pain scores at these points were significantly higher in group B than those in group A (both p < 0.01). The number of days required for a half reduction in wound pain, trotting, and full recuperation for group A were less than those for group B (p < 0.05). CONCLUSIONS: Epidural anesthesia, when used in laparoscopic surgery for infertility treatment, has advantages over general anesthesia in terms of analgesic effects, postoperative respiratory function, and a return to preoperative daily activities.

Adult↗
PubMed2004

Cerebral ischaemia during cardiac surgery in children detected by combined monitoring of BIS and near-infrared spectroscopy.

BACKGROUND: Children frequently suffer transient cerebral ischaemia during cardiac surgery. We measured cerebral ischaemia in children during cardiac surgery by combining two methods of monitoring. METHODS: We studied 65 children aged between 5 months and 17 yr having surgery to correct non-cyanotic heart disease using hypothermic cardiopulmonary bypass (CPB). During surgery, we measured the Bispectral Index (BIS) and regional cerebral haemoglobin oxygen saturation (SrO2) with near-infrared spectroscopy (NIRS). Cerebral ischaemia was diagnosed if both SrO2 and BIS decreased abruptly when acute hypotension occurred. In each patient, the relationship between SrO2 and arterial blood pressure (AP) was indicated by a plot of mean SrO2 against simultaneous mean AP. RESULTS: We noted 72 episodes of cerebral ischaemia in 38 patients. Sixty-three ischaemic events were during CPB. Cerebral ischaemia was less frequent in older patients. Cerebral ischaemia was more common and more frequent in children under 4 yr old. Haematocrit during CPB was lower and SrO2 was more dependent on AP in children under 4 yr. CONCLUSIONS: Children less than 4 yr of age are more likely to have cerebral ischaemia caused by hypotension during cardiac surgery. Ineffective cerebral autoregulation and haemodilution during CPB may be responsible.

Adolescent↗
PubMed2004

Is the ARX index a more sensitive indicator of anesthetic depth than the bispectral index during sevoflurane/nitrous oxide anesthesia?

BACKGROUND: During general anesthesia, hypnotic components have been monitored with electroencephalogram. The bispectral index is derived from a cortical electroencephalogram, but the A-line ARX index is the electroencephalographic response to auditory stimuli. The purpose of this study was to compare the changes of the A-line ARX index and the bispectral index during sevoflurane - nitrous oxide anesthesia. METHODS: One hundred females aged 30-60 years, and scheduled for partial mastectomy, were divided into two groups. Anesthesia was induced with sevoflurane 5% and nitrous oxide in oxygen for 3 min. A laryngeal mask airway was inserted, and anesthesia was maintained with sevoflurane 1-2% and nitrous oxide in oxygen. During surgery, the sevoflurane end-tidal concentration was kept at 0.5%, 1%, or 2% for 5 min before each measurement. Blood pressure, heart rate, and the A-line ARX index (n = 50), and the bispectral index (n = 50) were measured. RESULTS: Blood pressure and heart rate increased following laryngeal mask airway insertion and blood pressure decreased at 2% sevoflurane in both groups similarly. The A-line ARX index, but not the bispectral index, increased significantly by laryngeal mask airway insertion and skin incision. The A-line ARX index decreased at 2% sevoflurane compared with 0.5%, while the bispectral index remained unchanged. CONCLUSION: During sevoflurane-nitrous oxide anesthesia, the A-line ARX index might be a more sensitive indicator of anesthetic depth than the bispectral index.

Adult↗
PubMed2004

The frictional coefficient of the temporomandibular joint and its dependency on the magnitude and duration of joint loading.

In synovial joints, friction between articular surfaces leads to shear stress within the cartilaginous tissue, which might result in tissue rupture and failure. Joint friction depends on synovial lubrication of the articular surfaces, which can be altered due to compressive loading. Therefore, we hypothesized that the frictional coefficient of the temporomandibular joint (TMJ) is affected by the magnitude and duration of loading. We tested this by measuring the frictional coefficient in 20 intact porcine TMJs using a pendulum-type friction tester. The mean frictional coefficient was 0.0145 (SD 0.0027) after a constant loading of 50 N during 5 sec. The frictional coefficient increased with the length of the preceding loading duration and exceeded 0.0220 (SD 0.0014) after 1 hr. Application of larger loading (80 N) resulted in significantly larger frictional coefficients. In conclusion, the frictional coefficient in the TMJ was proportional to the magnitude and duration of joint loading.

Algorithms↗
PubMed2004

Shear properties of the temporomandibular joint disc in relation to compressive and shear strain.

Shear stress can result in fatigue, damage, and irreversible deformation of the temporomandibular joint disc. Insight into the dynamic shear properties of the disc may give insight into the mechanism inducing tissue failure due to shear. We tested the hypothesis that the dynamic shear properties of the disc depend on the amount of shear and compressive strain. Twenty-four porcine discs were used for dynamic shear tests. The specimens were clamped between the plates of a loading apparatus under compressive strains of 5%, 10%, and 15%. Dynamic shear was applied to the specimen by a sinusoidal strain of, respectively, 0.5%, 1.0%, and 1.5%. Both the dynamic elasticity and viscosity were proportional to compressive strain and inversely proportional to shear strain. These shear characteristics suggest a significant role of compressive and shear strain on the internal friction of the disc.

Algorithms↗
PubMed2004

Load independence of temperature-dependent Ca2+ recirculation fraction in canine heart.

Intramyocardial Ca(2+) recirculation fraction (RF) critically determines the economy of excitation-contraction coupling. RF is obtainable from the exponential decay of the postextrasystolic potentiation of left ventricular (LV) contractility. We have shown that RF remains unchanged despite increasing LV volume (LVV) at normothermia, but decreases with increasing temperature at a constant LVV. However, it remains unknown whether the temperature-dependent RF was not due to the simultaneously changed peak LV pressure (LVP) at a constant LVV. We hypothesized that this temperature-dependent RF would be independent of the simultaneous change in LVP. We used nine excised, cross-circulated canine hearts and allowed their LVs to contract isovolumically. During stable regular beats at 500 msec intervals, we inserted an extrasystolic beat at 360 msec interval followed by the postextrasystolic beats (PESs) at 500 msec intervals. We equalized the temperature-dependent peak LVPs of the regular beats at 36 degrees C and 38 degrees C to the peak LVP level of the stable regular beat at 33 degrees C by adjusting LVV. We fitted the same equation: nEmax = a.exp[-(i - 1)/tau(e)] + b.exp[-(i - 1)/tau(s)]cos[pi(i - 1)] + 1, used before to the normalized Emax (maximum elastance) values of PESi (i = 1-6) relative to the regular beat Emax. RF given by exp(-1/tau(e)) decreased by 19% to 38 degrees C from 33 degrees C. The temperature coefficient (Q(10)) of 1/RF was significantly greater than 1.3. The present results indicated a similar temperature dependence of RF and its Q(10) to those we observed previously without equalizing peak LVP. Thus, the temperature-dependent RF is independent of ventricular loading conditions.

Animals↗
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

Dynamic shear properties of the temporomandibular joint disc.

Shear stress might be an important factor associated with fatigue failure and damage of the temporomandibular joint disc. Little information, however, is available on the dynamic behavior of the disc in shear. Since the disc is an anisotropic and viscoelastic structure, in the present study the dependency of the dynamic shear behavior on the direction and frequency of loading was examined. Ten porcine discs were used for dynamic shear tests. Shear stress was applied in both anteroposterior (A-P test) and mediolateral (M-L test) directions. The dynamic moduli increased as the loading frequency increased. The dynamic elasticity was significantly larger in the A-P test than in the M-L test, although the dynamic viscosity was similar in both tests. The present results suggest that non-linearities, compression/shear coupling, and intrinsic viscoelasticity affect the shear material behavior of the disc, which might have important implications for the transmission of load in the temporomandibular joint.

Animals↗
PubMed2002

Biomechanical response of bovine temporomandibular joint disc to prolonged tensile stress.

This study was designed to evaluate the influence of prolonged tensile stress on the viscoelasticity of the temporomandibular joint (TMJ) disc. Twenty discs from 10, 3-year-old cattle were used. Tensile stress of 1.5 MPa was applied to specimens from the discs for 10, 20, 40 and 60 min. Following the prescribed period of tension for creep, the specimens were removed from the tension device and any recovery observed for 20 min. In all specimens, strain increased at the onset of stress application and reached almost steady conditions after 5 min. Although, the strain became slightly larger when the creep time was longer, no significant differences were found in the strains between any two tests with different periods of creep. The residual strain increased significantly with creep duration, and similarly the degree of recovery decreased significantly. In 10- and 20-min creep tests, the residual strains were 0.1 and 1.0%, the specimens in 40- and 60-min tests revealed irreversible changes in length. It was concluded that continuous loading for >40 min causes creep damage in bovine TMJ disc, and that prolonged sustained tension affects the recovery of joint homeostasis.

Animals↗
PubMed2002

The importance of tail temperature monitoring during tail-flick test in evaluating the antinociceptive action of volatile anesthetics.

BACKGROUND: Tail-flick (TF) latency can be influenced by tail-skin temperature (TT), and treatments that raise TT can mimic hyperalgesia on a TF test. As volatile anesthetics can raise TT via heat redistribution, their antinociceptive action can be hidden or obscured in a TF test. We tested the hypothesis that TT monitoring improves the efficiency of TF tests in evaluating the antinociceptive action of volatile anesthetics. METHODS: The relationship between TT and TF latency was first explored under varied TTs in 12 rats. Then, TT and TF latency were measured before and during isoflurane exposure (1.2%). In the low temperature group (n=6), rats were prewarmed mildly to increase TT during isoflurane exposure. In the high temperature group (n=6), rats were prewarmed enough to prevent a TT increase during isoflurane exposure. RESULTS: There was a highly significant correlation between TT and TF latency, that is, TF latency decreased as TT increased. In the low temperature group, there was a significant increase in TT during isoflurane exposure, while an increase in TF latency did not reach statistical significance. Tail-flick latency corrected by a change in TT showed a significant increase. In the high temperature group, TF latency increased significantly during isoflurane exposure without an increase in TT. CONCLUSIONS: Isoflurane inhalation can induce an increase in TT, which can obscure its antinociceptive action as evaluated by a TF test. Monitoring TT during a TF test is important to efficiently evaluate the antinociceptive action of volatile anesthetics.

Anesthetics, Inhalation↗
PubMed2002

Association of HLA-A*3303-B*4403-DRB1*1302 haplotype, but not of TNFA promoter and NKp30 polymorphism, with postherpetic neuralgia (PHN) in the Japanese population.

Herpes zoster is a common disease caused by reactivation of the varicella zoster virus (VZV). In a small number of herpes zoster patients, pain persists beyond 4 weeks or more after healing of vesicular eruptions; this condition is termed postherpetic neuralgia (PHN). Positive associations of human histocompatibility leukocyte antigens (HLA) class I antigens, A33 and B44, with PHN in the Japanese population have been reported. Our hypothesis is that susceptibility genes to PHN might exist in the HLA region and the study objective is to further examine possible associations of genes in HLA class I, II and III regions, HLA-A, -B, -DRB1, tumor necrosis factor alpha (TNFA) promoter, and a natural killer cell activating receptor, NKp30 polymorphisms with PHN. Although TNFA or NKp30 in the class III region had been considered as a candidate locus, we found no associations of TNFA promoter or NKp30 polymorphisms with PHN in this study. We demonstrated that HLA-A*3303, -B*4403 and -DRB1*1302 alleles were significantly associated with PHN (P = 0.0007 for A*3303, P = 0.001 for B*4403 and P = 0.001 for DRB1*1302). The frequency of the HLA-A*3303-B*4403-DRB1*1302 haplotype was also significantly higher in the PHN patients than in the healthy controls (P = 0.0039). Our results suggest that this haplotype might be related to the pathogenesis of PHN.

Adult↗
PubMed2001

Self-reported recovery time of daily activity after bone marrow harvesting from healthy donors.

PURPOSE: The study was planned to describe and compare the resumption of daily activity after bone marrow harvesting (BMH) under general anesthesia with different anesthetic agents, isoflurane, sevoflurane and propofol. METHODS: Sixty-five adult healthy allogenic donors (26 women, 39 men; 37.0 +/- 9.5 years of age; ASA class I or II) were studied. BMH was performed under general anesthesia with isoflurane, sevoflurane, or propofol as the main anesthetic agent. On day 1, donors were asked how soon they could resume five daily activities: talking, walking, drinking, eating, and reading. RESULTS: Although there was considerable variation in resumption time within and among these five activities, 77% of donors resumed all of these basic daily activities within 12 h after BMH. Donors who received propofol resumed talking significantly faster than those who received sevoflurane or isoflurane, but the choice of main anesthetic agent did not affect the time of resumption of other activities. Lower preoperative hemoglobin concentration and greater decline of hemoglobin concentration on day 1 were significantly associated with slower resumption of walking and reading. CONCLUSION: Although the choice of main anesthetic agent and anemia affected postoperative recovery, 77% of donors could resume these five daily activities within 12 h.

Journal Article↗
PubMed2001

Occurrence of organo-arsenicals in jellyfishes and their mucus.

Water-soluble arsenic compound fractions were extracted from seven species of jellyfishes and subjected to analysis by high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) for arsenicals. A low content of arsenic was found to be the characteristic of jellyfish. Arsenobetaine (AB) was the major arsenic compound without exception in the tissues of the jellyfish species and mucus-blobs collected from some of them. Although the arsenic content in Beroe cucumis, which preys on Bolinopsis mikado, was more than 13 times that in B. mikado, the chromatograms of these two species were similar in the distribution pattern of arsenicals. The nine species of jellyfishes including two species treated in the previous paper can be classified into arsenocholine (AC)-rich and AC-poor species. Jellyfishes belonging to Semaostamae were classified as AC-rich species.

Animals↗