Biomedical subjects

E Tanaka

Publications and source records attributed to E Tanaka.

At least 37 records · Page 2Linked to original sources

PubMed2004

Interferon treatment improves survival in chronic hepatitis C patients showing biochemical as well as virological responses by preventing liver-related death.

Interferon therapy for chronic hepatitis C reduces the risk of hepatocellular carcinoma, especially among virological and biochemical responders. However, little is known about the effect of interferon therapy on mortality. We studied the long-term effect of interferon therapy on mortality in patients with chronic hepatitis C. For this retrospective cohort study, 2954 patients with chronic hepatitis C were recruited, of whom 2698 received interferon therapy and 256 did not. The effect of interferon therapy on survival was assessed by standardized mortality ratio (SMR) based on published mortality data for the general Japanese population and by risk ratio calculated by proportional hazard regression. Over 6.0 +/- 2.2 years follow-up, death from liver-related diseases was observed in 69 (68%) of 101 deaths among interferon-treated patients and in 42 (81%) of 52 deaths among untreated patients. Compared with the general population, overall mortality was high among untreated patients (SMR: 2.7; 95% CI: 2.0-3.6) but not among interferon-treated patients (SMR: 0.9; 95% CI: 0.7-1.1). Liver-related mortality was extremely high among untreated patients (SMR: 22.2; 95% CI: 16.0-30.0) and less among interferon-treated patients (SMR: 5.5; 95% CI: 4.3-6.9). The risk of death from all causes was lower for interferon-treated than untreated patients (risk ratio: 0.47; 95% CI: 0.261-0.836; P = 0.01). The risk of death from liver-related diseases was significantly lower for sustained virological responders (risk ratio: 0.04; 95% CI: 0.005-0.301; P = 0.002) compared with untreated patients, but not for nonsustained virological responders. Sustained biochemical responders (risk ratio: 0.03; 95% CI: 0.004-0.230; P < 0.001) and transient biochemical responders (risk ratio: 0.18; 95% CI: 0.063-0.532; P = 0.002) showed a significantly reduced risk of death from liver-related death, whereas biochemical nonresponders did not. Hence interferon treatment improved survival in chronic hepatitis C patients showing a biochemical as well as a virological response by preventing liver-related deaths.

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↗

PubMed2003

Musculoskeletal disorders among hospital nurses in rural Japan.

INTRODUCTION: Although musculoskeletal disorders (MSD) represent a significant occupational problem for hospital nurses, few investigations target nurses in rural facilities. This study investigated the prevalence and correlates of MSD among nurses within an affiliated hospital conglomerate of rural Japan. METHODS: A self-reporting survey was used as diagnostic tool; the reliability, validity and cost-effectiveness of this method has been established. RESULTS: An initial group of 329 nurses was recruited from three affiliated, rural locations in Yamanashi prefecture, central Japan; 247 usable replies were obtained (final response rate: 75.1%). The 12-month period-prevalence of self-reported MSD at any body site was 91.9% (95% CI 87.8-94.7). Low back pain (LBP) was the most commonly reported MSD with a prevalence of 82.6% (95% CI 77.4-86.8). Next most reported were shoulder (61.1%, 95% CI 54.9-67.0), neck (36.8%, 95% CI 31.1-43.0), upper back (29.1%, 95% CI 23.8-35.1), knee (23.5%, 95% CI 18.6-29.1) and upper leg MSD (19.4%, 95% CI 15.0-24.8). MSD of the wrist (14.2%, 95% CI 10.4-19.1), upper arm (13.0%, 95% CI 9.3 -17.7) and lower arm (11.7% 95% CI 8.3-16.4) were less common. Logistic regression indicated that nurses who were regularly involved in the manual handling of patients had an increased LBP risk of 16.7 (OR 16.7, 95% CI 1.3-412.7, p = 0.0340) when compared with nurses who were not involved in manual handling of patients. CONCLUSION: Overall, our study indicated that MSD is common among rural Japanese nurses and its prevalence is consistent between related facilities. The excessive amount of LBP, however, suggests that Japanese nurses are at higher risk of this condition compared with their foreign counterparts.

Journal Article↗

PubMed2003

Arachidonic acid metabolites contribute to the irreversible depolarization induced by in vitro ischemia.

Intracellular recordings were made from hippocampal CA1 neurons in rat slice preparations. Superfusion with oxygen- and glucose-deprived medium (in vitro ischemia) produced a rapid depolarization approximately 5 min after the onset of the superfusion. Even when oxygen and glucose were reintroduced immediately after rapid depolarization, the membrane depolarized further (persistent depolarization) and reached 0 mV (irreversible depolarization) after 5 min from the reintroduction. The pretreatment of the slice preparation with a phospholipase A2 (PLA2) inhibitor, para-bromophenacyl bromide, or a cytochrome p-450 inhibitor, 17-octadecynoic acid, significantly restored the membrane to the preexposure potential level after the reintroduction of oxygen and glucose. The administration of 14,15-epoxyeicosatrienoic acid or 20-hydroxyeicosatetraenoic acid did not change the latency of the rapid depolarization and did not allow the membrane potential to recover after the ischemic exposure. In contrast, after pretreatment with cyclooxygenase or lipoxygenase inhibitors, such as indomethacin, resveratrol, Dup-697, nordihydroguaiaretic acid, and 3,4-dihydrophenyl ethanol, a minority of neurons tested showed postischemic recovery from the persistent depolarization. Improved recovery was also seen after treatment with the free radical scavengers, edaravone and alpha-tocopherol. These results suggest that the activation of the arachidonic acid cascade via PLA2 and the free radicals produced by arachidonic acid metabolism contribute to the irreversible depolarization produced by in vitro ischemia.

Action Potentials↗

PubMed2003

Portal vein resection and reconstruction prior to hepatic dissection during right hepatectomy and caudate lobectomy for hepatobiliary cancer.

BACKGROUND: Hepatobiliary cancer invading the hilar bile duct often involves the portal bifurcation. Portal vein resection and reconstruction is usually performed after completion of the hepatectomy. This retrospective study assessed the safety and usefulness of portal vein reconstruction prior to hepatic dissection in right hepatectomy and caudate lobectomy plus biliary reconstruction, one of the common procedures for radical resection. METHODS: Clinical characteristics and perioperative results were compared in patients who underwent right hepatectomy and caudate lobectomy plus biliary reconstruction with (ten patients) and without (11 patients) portal reconstruction from September 1998 to March 2002. RESULTS: All ten portal vein reconstructions were completed successfully before hepatic dissection; the portal cross-clamp time ranged from 15 to 41 (median 22) min. Blood loss, blood transfusion during the operation, postoperative liver function, morbidity and length of hospital stay were similar in the two groups. No patient suffered postoperative hepatic failure or death. CONCLUSION: This study demonstrates that portal vein reconstruction does not increase the morbidity or mortality associated with right hepatectomy and caudate lobectomy with biliary reconstruction. This approach facilitates portal vein reconstruction for no-touch resection of hepatobiliary cancer invading the hilar bile duct.

Aged↗

PubMed2003

Long-term follow-up of hepatitis C virus infection: HLA class II loci influences the natural history of the disease.

Hepatitis C virus (HCV) causes various grades of chronic liver disease, ranging from an asymptomatic state to cirrhosis. To assess genetic factors of disease severity, we selected two HCV patient groups according to the following stringent criteria: (i) asymptomatic carrier state (ASC) defined by HCV infection for more than 20 years, normal alanine aminotransferase levels for the past 5 years as well as normal liver histology and/or shape and (ii) liver cirrhosis (LC) as diagnosed by clinical symptoms, liver biopsy and/or ultrasonography. A total of 103 chronically infected Japanese HCV patients (43 ASC and 60 LC) were analyzed. HLA class I and II alleles were established using low resolution DNA typing. HLA-DRB1 and DQB1 genotypes were inferred upon polymerase chain reaction-restriction fragment length polymorphism analysis. Two hundred and one anti-HCV-negative ethnically matched controls were included. The frequencies of DRB1*12 (*1201 and *1202), DQB1*0301 and DRB3*03 alleles were higher in patients with ASC than in those with LC (odds ratio (OR) 11.23, OR 4.25, and OR 3.22, respectively). The frequency of DQB1*0503 were lower in ASC patients compared to LC patients (OR 0.05). No significant differences between groups were observed for age, sex, source of infection, HCV genotype or viral loads. Our findings establish that certain HLA class II alleles strongly influence disease progression following HCV infection.

Aged↗

PubMed2003

Toxicological interactions involving psychiatric drugs and alcohol: an update.

This review focuses on the toxicological interactions between alcohol (ethanol) and psychiatric drugs (antidepressants and antipsychotics), including those leading to fatal poisoning. Acute or chronic ingestion of alcohol when combined with psychiatric drugs may lead to several clinically significant toxicological interactions. The metabolism of these drugs is generally but not always delayed by acute alcohol ingestion. Drugs undergoing metabolism may also show increased metabolic clearance with chronic alcohol ingestion. Therefore, the net effect may be influenced by internal (e.g. disease, age, gender), external (e.g. environment, diet) and pharmacokinetic (e.g. dose, timing of ingestion, gastrointestinal absorption, distribution and elimination) factors. Cases of fatal poisoning involving coadministration of psychiatric drugs, alcohol and other drugs prompted this review.

Adult↗

PubMed2003

How useful is the "cocktail approach" for evaluating human hepatic drug metabolizing capacity using cytochrome P450 phenotyping probes in vivo?

Relatively selective in vivo substrate probes have been developed for several major CYP isoforms involved in oxidative drug metabolism. There are basically two in vivo methods for identifying the phenotype. One method, the selective (CYP-specific) phenotyping method, involves administering one single probe drug, whereas the other is a mixed phenotyping or "cocktail" method involving the simultaneous administration of multiple probe drugs, specific for the individual P450. At present, caffeine and chlorzoxazone are used most often as probe drugs for CYP1A2 and CYP2E1, respectively, but these are not necessarily the best probe drugs. Of the potential probe drugs for CYP2C9, CYP2C19, CYP2D6 and CYP3A4, none is really useful. Despite current limitations, the cocktail method for obtaining information about multiple CYP activities in a single experimental session is likely to be more widely used as a screening or phenotyping method for humans in the future.

Aryl Hydrocarbon Hydroxylases↗

PubMed2003

Involvement of cytochrome P450 2C9, 2E1 and 3A4 in trimethadione N-demethylation in human microsomes.

BACKGROUND AND OBJECTIVES: Trimethadione (TMO), an antiepileptic drug, may be used as a candidate for estimating hepatic drug-oxidizing activity. While TMO metabolism is mainly catalysed by CYP2C9, CYP2E1 and CYP3A4 the contribution of the different isoforms is unclear. In this study, we determined the percentage contribution of the three CYPs (CYP2C9, CYP2E1 and CYP3A4) to TMO N-demethylation. METHOD: We used human liver microsomes and human recombinant CYPs expressed in human B-lymphoblast cells and baculovirus-infected insect cells. RESULTS: The mean Km, Vmax and Vmax/Km values of TMO N-demethylation in human microsomes were 3.66 (mm), 503 (pmol/min/mg) and 2.61 (mL/h/mg), respectively. In the microsomes from human B-lymphoblast cells or baculovirus-infected insect cells, CYP 2C9, CYP 2E1 and CYP3A4 exhibited similar Km and higher Vmax in baculovirus-infected insect cells than B-lymphoblast cells. In baculovirus-infected insect cells, CYP2C9, CYP2E1 and CYP3A4 exhibited activities of 32, 286 and 77 pmol/min/pmol CYP, respectively. No CYP activity catalysed by CYP1A2 and 2D6 were detected in the two human cDNA expressed CYP isoforms. CONCLUSION: TMO is metabolized not only by CYP2E1 but also CYP3A4 and CYP2C9. The order of this metabolism is as follows: CYP2E1 >> CYP3A4 > CYP2C9.

Anticonvulsants↗

PubMed2003

Postnatal development of protein gene product 9.5 and calcitonin gene-related peptide immunoreactive nerve fibres in rat temporomandibular joint disc.

Protein gene product 9.5 (PGP 9.5), an immunohistochemical marker of whole nerve fibres, and calcitonin gene-related peptide (CGRP), a marker of thin nerve fibres, were used to elucidate the postnatal development of nerve fibres in rat temporomandibular joint (TMJ) disc. At birth, PGP 9.5-immunoreactive nerve fibres exhibited running towards the central area of the disc, invading by approximately 95 m from the disc attachment. The nerve fibres existing inside the disc became longer during postnatal development. The number of nerve fibres in the disc increased in a progressive manner up to 40 days after birth. CGRP-immunoreactive nerve fibres also presented changes essentially similar to those of PGP 9.5-immunoreactive nerve fibres. However, the proportion of CGRP-immunoreactive nerve fibres to PGP 9.5-immunoreactive ones was approximately 80%, and remained constant up to 40 days after birth. In conclusion, the distribution and the number of nerve fibres are variable during postnatal development, although the ratio of thin nerve fibres remains invariable. It is emphasized that these changes of innervation in the TMJ are associated with the development of masticatory function.

Animals↗

PubMed2003

Expression of c-Fos protein in the trigeminal nuclear complex resulting from quantified force application to the rat molar.

This study was conducted to investigate the expression and distribution of c-Fos-like immunoreactive neurones (Fos-neurones), in the rat trigeminal sensory nuclear complex, produced by mechanical forces with various magnitudes and durations applied to the left upper first molar. The magnitudes of forces applied to the tooth were 25, 50 and 100 g and the duration was 2 h. A quantified force of 100 g was also applied to the upper molar for varying durations [short-time (1-2 min)], 2, 4, 8 and 12 h. Fos-neurones distributed in the bilateral superficial laminae of the subnucleus caudalis, and the ipsilateral dorsomedial part of subnucleus oralis (Sp5Odm). The number of Fos-neurones increased in the subnucleus caudalis (Sp5C) according to the force magnitude. In the Sp5C, the number of Fos-neurones exhibited maximum level, 2 or 4 h after the application. In the Sp5Odm, however, the number of Fos-neurones reached the maximum level at 8 h. These data suggest that the change in the number of nociceptive neurones in Sp5C reflect changes in encoding the magnitude of force to tooth, and that the nature of pain response to orthodontic forces might have some relation to the delayed expression of c-Fos protein in the Sp5Odm.

Animals↗

PubMed2003

Correlation between maximum bite force and craniofacial morphology of young adults in Indonesia.

The present study was conducted to evaluate the relationship between maximum bite force and craniofacial morphology. Sixty-four Indonesian female dental students aged 19-27 years with normal occlusion served as the subjects. The Dental Prescale System was used to measure the maximum bite force using a pressure sensitive sheets while craniofacial morphology measurements were determined from conventional lateral radiograms. The antero-posterior and right-left position of the occlusal load centre (the OLC) were measured also. Stepwise multiple regression analysis was performed to evaluate the relationship between bite force and craniofacial morphology while correlation analysis was used to evaluate the antero-posterior position of the OLC related to craniofacial morphology. Fifty-five per cent of the bite force could be explained by variations in the posterior facial height, gonial angle, antero-posterior size of the maxilla, and posterior length of the cranial base. The result showed a larger bite force implies a greater posterior facial height, smaller gonial angle, larger maxilla and straighter posterior length of the cranial base. This study suggests that among Indonesians, maximum bite force could be explained by craniofacial morphology as found in Caucasians. In addition, we proposed a clinical standard of the OLC for the comprehensive evaluation of occlusion.

Adult↗

PubMed2003

Association between condylar position, joint morphology and craniofacial morphology in orthodontic patients without temporomandibular joint disorders.

The present study investigated condylar position and joint morphology in adolescent patients and elucidated the possible association between the joint structure and condylar position, and craniofacial morphology. Sixty-five adolescent patients were selected as subjects and their tomograms and lateral cephalograms were analysed. No significant differences in joint spaces were found between the right and left temporomandibular joints. Both the condyles in this population were located slight anteriorly in the glenoid fossa. With respect to the association between condylar position, joint morphology and craniofacial morphology, the ramus plane angle also exhibited significant negative correlations with posterior, lateral and medial joint spaces. Furthermore, there was a significant negative correlation between the gonial angle and the anterior joint space. These findings imply that the condyle was likely to show more posterior position in the glenoid fossa when the mandible exhibited clockwise rotation. In conclusion, the condyle in the adolescent subjects showed a symmetrical anterior position relative to the glenoid fossa. In addition, the joint spaces and it ratios were significantly related to the craniofacial morphology associated with vertical dimension. It is suggested that the condylar position may be affected by craniofacial growth pattern.

Adolescent↗

PubMed2003

Clinical evaluation of a new enzyme immunoassay for hepatitis B virus core-related antigen; a marker distinct from viral DNA for monitoring lamivudine treatment.

We aimed to assess the clinical performance of a newly developed chemiluminescence enzyme immunoassay (CLEIA) for the detection of hepatitis B virus (HBV) core-related antigen (HBcrAg) in patients with chronic HBV infection. A total of 82 patients with chronic HBV infection and 167 HBV-negative controls were studied. HBcrAg was measured by CLEIA with monoclonal antibodies to hepatitis B e antigen (HBeAg) and hepatitis B core antigen (HBcAg), and HBV DNA was measured by transcription-mediated amplification assay (TMA) and in-house real-time detection polymerase chain reaction (RTD-PCR). The HBcrAg assay detected viremia in 189 of 216 samples (88%) collected from 72 patients whilst the TMA assay detected viremia in 178 of the 216 samples (82%) (P = 0.019). The HBcrAg concentration correlated linearly with the HBV DNA concentration (P < 0.001) over a range which varied 100 000-fold. The accuracy in the measurement of the patients' HBV load obtained using the HBcrAg assay was not affected by the absence of hepatitis B e antigen from the serum or the presence of precore mutations in the HBV genome. In patients without anti-viral drugs, changes in their serum HBcrAg concentration over time corresponded to their HBV DNA concentration. In six additional patients who were later treated with lamivudine, HBV DNA concentration declined more rapidly than their HBcrAg concentration. Three months after treatment commenced, the ratio of HBcrAg: HBV DNA had increased in all six patients (P = 0.031). The HBcrAg assay is a sensitive and useful test for the assessment of a patient's HBV load. When monitoring the anti-viral effect of lamivudine, HBcrAg provides a viral marker which is independent of HBV DNA.

Biomarkers↗

PubMed2003

Impaired cough reflex in patients with recurrent pneumonia.

BACKGROUND: A substantial proportion of patients with recurrent pneumonia do not have an apparent underlying condition, but they may have unknown defects in host defence mechanisms such as cough reflex. METHODS: Capsaicin cough sensitivity was measured in seven patients with recurrent pneumonia but no underlying condition. Recurrent pneumonia was defined as at least two episodes of pneumonia in 1 year, or three or more episodes at any time. After remission of pneumonia, 10 doubling concentrations of capsaicin (1.22-625 microM) were inhaled until five or more coughs were induced (cough threshold). Mucociliary clearance was assessed on the basis of nasal ciliary beat frequency and nasal clearance time. Twenty one age and sex matched healthy subjects were studied as controls. RESULTS: Each patient had 2-6 episodes of pneumonia. Most episodes developed in dependent lung segments, suggesting the involvement of silent aspiration. Log transformed cough threshold was significantly higher in patients than in controls (mean 2.37 M (95% CI 1.84 to 2.90) v 1.29 microM (95% CI 1.11 to 1.47); p<0.0001). The effect of pneumonia per se on cough reflex seemed unlikely since the cough threshold showed little change when re-examined after 3 months. The patients and controls did not differ with respect to the indices of mucociliary clearance. CONCLUSIONS: Impaired cough reflex may be involved in the pathogenesis of recurrent pneumonia.

Adult↗

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

The presynaptic modulation of glutamate release and the membrane dysfunction induced by in vitro ischemia in rat hippocampal CA1 neurons.

Superfusion with an oxygen and glucose deprived medium (in vitro ischemia) of rat hippocampal CA1 pyramidal neurons in tissue slices produced a rapid depolarization within 5 min and thereafter showed no functional recovery (irreversible membrane dysfunction), even if oxygen and glucose were reintroduced. We previously suggested that such a rapid depolarization is triggered by the accumulation of extracellular glutamate (Glu). As a result, we examined the effects of either the activation or inhibition of presynaptic receptors, which modulate Glu release from the nerve terminal, on the potential change produced by in vitro ischemia. The adenosine A1 receptor antagonist, 8-cyclopenthyl theophylline, A2a receptor antagonist, ZM241385, and A2b receptor antagonist, alloxazine, did not significantly alter either the latency or the maximal slope of the rapid depolarization. In addition, the GABAB receptor antagonist, 2-hydroxysaclofen, or the metabotropic Glu receptor type 4 antagonist, alpha-methylserine-O-phosphate, did not change either the latency or the maximal slope. The adenosine A(1) receptor agonist, 2-chloro-N6-cyclopentyladenosine, A2a receptor agonist, CGS2168, or A2b receptor agonist, 5'-(N-ethylcarboxamido)-adenosine, did not affect these parameters either. None of these drugs restored the membrane potential to the pre-exposure level after the reintroduction of oxygen and glucose. Simultaneous intracellular recordings from CA1 and CA3 pyramidal neurons in the same slices revealed the membrane of the CA3 neurons to be hyperpolarized when a rapid depolarization occurred in the CA1 neurons. These results suggest that presynaptic Glu release does not accelerate during the generation of the rapid depolarization induced by in vitro ischemia.

Adenosine↗