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Biomedical subjects

R Tanaka

Publications and source records attributed to R Tanaka.

At least 19 recordsLinked to original sources

Neonatal cavernous angioma located in the basal ganglia with profuse intraoperative bleeding.

CASE REPORT: A rare case of congenital cavernous angioma detected during pregnancy is described. The tumor was pointed out by ultrasound in a fetus at 39 weeks gestation. The male baby was delivered by cesarean section. Computed tomography and magnetic resonance imaging revealed a tumor in the left basal ganglia. Because the tumor gradually enlarged and right hemiparesis became evident, a decision was made to remove the tumor. Because of profuse intraoperative bleeding, surgical total removal was not accomplished. Histopathological specimens revealed cavernous angioma. The patient was treated postoperatively with 30.4 Gy of local irradiation. His right hemiparesis improved and the tumor gradually decreased in size. DISCUSSION: The literatures are reviewed and discussed about clinical features and management controversies of this rare tumor.

Basal Ganglia↗

Ruptured intracranial aneurysm following gamma knife surgery for acoustic neuroma.

A-63-year-old woman underwent gamma knife surgery (GKS) for acoustic neuroma. Six years later, she suffered sudden onset of severe headache followed by a disturbance of consciousness and subarachnoid haemorrhage due to a ruptured aneurysm originating from the distal anterior inferior cerebellar artery. The aneurysm was not located at a branching site and was included within the radiation field. The aneurysm was treated by endovascular embolization, and now, 15 months later, the patient has recovered satisfactorily. This is the first report of aneurysm formation following GKS for acoustic neuroma.

Basilar Artery↗

In vivo IL-10 gene delivery attenuates bleomycin induced pulmonary fibrosis by inhibiting the production and activation of TGF-beta in the lung.

BACKGROUND: Idiopathic pulmonary fibrosis is a devastating disorder for which there is no effective treatment. Transforming growth factor (TGF)-beta plays a critical role in provoking fibrosis. Interleukin (IL)-10 is a potent immunosuppressive cytokine but its effect on the fibrosing process is unclear. A study was undertaken to examine whether IL-10 affects the production and activation of TGF-beta and thus can attenuate the fibrosis. METHODS: Mice were given an intratracheal injection of bleomycin. On day 1 or 14, IL-10 gene was delivered by rapid intravenous injection of Ringer's solution containing plasmid. Two weeks after the plasmid injection the mice were examined for fibrosis. The effect of IL-10 on TGF-beta production by alveolar macrophages was assessed. RESULTS: Even when delivered during the fibrosing phase, IL-10 gene significantly suppressed the pathological findings, hydroxyproline content, and production of both active and total forms of TGF-beta1 in the lung. Immunohistochemical analyses showed that alveolar macrophages were one of the major sources of TGF-beta1 and IL-10 diminished the intensity of the staining. IL-10 also suppressed the expression of alphaV beta6 integrin, a molecule that plays an important role in TGF-beta activation, on lung epithelial cells. Alveolar macrophages from bleomycin injected mice produced TGF-beta1 spontaneously ex vivo, which was significantly suppressed by treatment of the mice in vivo or by treatment of the explanted macrophages ex vivo with IL-10. CONCLUSION: IL-10 suppresses the production and activation of TGF-beta in the lung and thus attenuates pulmonary fibrosis, even when delivered in the chronic phase.

Animals↗

Identification of expressed genes characterizing long-term survival in malignant glioma patients.

Better understanding of the underlying biology of malignant gliomas is critical for the development of early detection strategies and new therapeutics. This study aimed to define genes associated with survival. We investigated whether genes coupled with a class prediction model could be used to define subgroups of high-grade gliomas in a more objective manner than standard pathology. RNAs from 29 malignant gliomas were analysed using Agilent microarrays. We identified 21 genes whose expression was most strongly and consistently related to patient survival based on univariate proportional hazards models. In six out of 10 genes, changes in gene expression were validated by quantitative real-time PCR. After adjusting for clinical covariates based on a multivariate analysis, we finally obtained a statistical significance level for DDR1 (discoidin domain receptor family, member 1), DYRK3 (dual-specificity tyrosine-(Y)-phosphorylation-regulated kinase 3) and KSP37 (Ksp37 protein). In independent samples, it was confirmed that DDR1 protein expression was also correlated to the prognosis of glioma patients detected by immunohistochemical staining. Furthermore, we analysed the efficacy of the short interfering RNA (siRNA)-mediated inhibition of DDR1 mRNA synthesis in glioma cell lines. Cell proliferation and invasion were significantly suppressed by siRNA against DDR1. Thus, DDR1 can be a novel molecular target of therapy as well as an important predictive marker for survival in patients with glioma. Our method was effective at classifying high-grade gliomas objectively, and provided a more accurate predictor of prognosis than histological grading.

Adolescent↗

Dependence of fragmentation behavior of colloidal aggregates on their fractal structure.

The fragmentation dynamics of aggregate of non-Brownian particles in shear flow is investigated numerically. The breakup behaviors of aggregates having the same connectivity but the different space-filling properties are examined. The Lagrangian particle simulation in a linear flow field is performed. The effect of surrounding fluid on the motion of multiple particles is estimated by Stokesian dynamics approach. The inter-particle force is calculated from the retarded van der Waals potential based on the Lifshitz theory. The results obtained in this work indicate that the fragmentation behavior of colloidal aggregates depends on their fractal structure. However, if the resultant aggregate size is smaller than the critical one, the fragmentation behavior shows the universality regardless of their original structure. Furthermore, the restructuring of aggregate in shear flow and its effect on the fragmentation process are also discussed.

Journal Article↗

Surgical management of a double-chambered right ventricle and chylothorax in a Labrador retriever.

A 22-month-old, male Labrador retriever was presented with anorexia, dyspnoea, and fainting. The dog was diagnosed with a double-chambered right ventricle and tricuspid valve dysplasia using echocardiography and cardiac catheterisation. A marked bilateral pleural effusion was also present and chemical analysis of the fluid confirmed the diagnosis of chylothorax. Using echocardiography, a pressure gradient of 87.1 mmHg was found between the proximal and distal chambers of the double-chambered right ventricle. Initiation of cardiopulmonary bypass allowed the anomalous muscle bundle that divided the right ventricle into two chambers to be resected via a right ventriculotomy. The fainting completely resolved postoperatively, and this treatment seemed quite effective in the reduction of pressure overload ascribable to ejection disturbance. Because the tricuspid dysplasia was not corrected in the first operation, the postoperative chyle effusion was reduced but did not cease. A combination of thoracic duct ligation and passive pleuroperitoneal shunting was effective in the resolution of the chyle effusion.

Animals↗

Surgical correction of ventricular septal defect with aortic regurgitation in a dog.

An 8-month-old entire Miniature Dachshund, weighing 4.2 kg, was presented for examination following delvelopment of a cough. Ventricular septal defect had been diagnosed tentatively in its infancy on the basis of a cardiac murmur detected by auscultation and echocardiography. Echocardiography using a B mode right parasternal long-axis view showed a defect at the atrioventricular junction and a thickened cusp of the aortic valve prolapsing into the defect. Colour-flow Doppler showed shunt blood flow across the defect at the level of the atrioventricular junction, from left to right. The sinus of Valsalva was dilated, with turbulent blood flow. Aortic regurgitation was also observed. Cardiac catheterisation studies confirmed the diagnosis of a supracristal ventricular septal defect with aortic regurgitation. Despite medication with digoxin, enalapril and aminophylin, started from the first admission, left ventricular internal dimensions gradually increased, and fractional shortening of the left ventricle gradually decreased. Surgery, with the aid of extracorporeal circulation, to close the ventricular septal defect, was performed 1 year after the initial examination. The aortic valve was left untreated. Postoperatively, the systolic murmur disappeared. Shunt flow from the left to the right ventricle was no longer observed on echocardiography, however there was still a small amount of aortic regurgitation during diastole visualised with colour-flow Doppler echocardiography. The prolapse of the cusp of the aortic valve on B-mode echocardiography was no longer observed and thickening of the cusp had not progressed. Left ventricular function measurement using M mode echocardiography showed a reduced left ventricular volume overload with reduced left ventricular internal dimensions and increased fractional shortening. The cough was relieved and no follow-up medication was scheduled. Early surgical closure of the ventricular septal defect improved the patient's condition and controlled prolapse and thickening of the aortic valve.

Animals↗

Abnormal muscle response monitoring during microvascular decompression for hemifacial spasm.

BACKGROUND: Several studies have investigated the relation between intraoperative abnormal muscle response (AMR) findings and postoperative results in patients undergoing microvascular decompression (MVD) for hemifacial spasm (HFS). However, there is some debate over the reliability of AMR as an indicator of postoperative outcome. We investigated whether AMR findings obtained during MVD reflect postoperative outcome in patients with HFS. METHOD: Subjects were 60 HFS patients who underwent AMR monitoring during MVD. AMR recordings were obtained from the mentalis muscle by electrical stimulation of the temporal branch of the facial nerve and from the orbicularis oculi muscles by stimulation of the marginal mandibular branch. Surgical outcome was compared with AMR findings at the completion of MVD. Mean follow-up was 61 months. FINDINGS: HFS resolved completely in 50 patients in whom AMR disappeared intraoperatively and in 5 patients in whom the AMR amplitude was decreased at the end of MVD. Four patients showed HFS at the final follow-up examination despite cessation or decrease of AMR during surgery. In 1 patient, preoperative AMR waveforms persisted throughout MVD, but the postoperative outcome was excellent. CONCLUSIONS: Our findings suggest that intraoperative cessation or decreased amplitude of AMR at the end of surgery indicates a high likelihood of postoperative relief of HFS. We believe that intraoperative AMR monitoring is useful in MVD surgery for HFS.

Adult↗

Simultaneous multi-section perfusion CT and CT angiography for the assessment of acute ischemic stroke.

BACKGROUND: Introduction of helical computed tomography (CT) scanning has enabled rapid imaging of the vascular status by means of CT angiography and perfusion CT. By virtue of recent multi-detector technology, helical CT has the ability to perform both CT angiography and multi-section perfusion CT simultaneously. This study investigated the clinical feasibility of simultaneous assessment of perfusion CT and CT angiography in patients with acute ischemic stroke. METHOD: Perfusion CT and CT angiography were performed simultaneously in a series of consecutive 31 acute ischemic stroke patients. The time required for the entire processing was about 15 minutes. Contrast agent was used in a total dose of 100 ml (35 ml for perfusion CT and 65 ml for CT angiography). FINDINGS: Simultaneous perfusion CT scans and CT angiographies were of diagnostic quality for 29 patients (94%). In large territorial infarct patients, perfusion CT could predict all perfusion deficits of the final lesions (10 out of 10 lesions) and CT angiography could detect 9 of 10 occlusions of major cerebral arteries (90%). In patients with small lacunar or subcortical infarcts, perfusion CT could predict 9 out of 19 lesions (47.4%), and false-negative were encountered in small lesions (three patients) or in inadequate coverage of data acquisition (seven patients). Acute stage thrombolytic intervention could be carried out based on the findings, and the success of thrombolytic therapy could be demonstrated by follow-up study. CONCLUSIONS: Simultaneous perfusion CT and CT angiography is the very useful tool for the rapid and adequate diagnosis of almost all of the large territorial infarcts and some of non-territorial lacunar infarcts. It is an easy-to-perform and safe imaging technique to assess acute ischemic stroke.

Acute Disease↗

Curved varus femoral osteotomy for minimal dysplastic hip in patients older than 45 years of age: comparison with rotational acetabular osteotomy.

Periacetabular osteotomies, such as rotational acetabular osteotomy (RAO) for osteoarthritis (OA) secondary to hip dysplasia, have produced satisfactory medium- and long-term results in early OA. However, as the degree of surgical invasion of these procedures is comparatively major and long-term postoperative rehabilitation is required, this procedure is generally not indicated for those in the fifth and sixth decades of life. Curved varus femoral osteotomy (CVO), which is a less invasive procedure, is considered a worthwhile option, although to the best of our knowledge no comparative study has been reported on these two procedures in older patients. We performed a comparative study on the outcomes of CVO for minimal dysplasia of the hip with a center-edge (CE) angle greater than 5 degrees in 15 patients (15 joints) older than 45 years of age at a mean period of 8 years after surgery and on the outcomes of RAO in 16 patients (18 joints) performed during the same period. No significant difference was observed between the two groups regarding the Merle d'Aubigne score during follow-up. Progression of osteoarthritis was radiologically observed during follow-up in three hips in the CVO group and in one hip in the RAO group. Kaplan-Meier survivorship analysis, with radiological progression of osteoarthritis as the endpoint, predicted a survival rate of 75% at 10 years in the CVO group. In the RAO group the predicted 10-year survival rate was 94%, demonstrating no significant difference between the two groups. CVO is a less invasive surgical technique than RAO, requires a comparatively shorter period of postoperative rehabilitation, and is useful as a joint-preserving procedure in older patients with minimal dysplasia of the hip with unilateral involvement. CVO should be selected for elderly patients with a CE angle greater than 5 degrees .

Acetabulum↗

Highly optimised global organisation of metabolic networks.

High-level, mathematically precise descriptions of the global organisation of complex metabolic networks are necessary for understanding the global structure of metabolic networks, the interpretation and integration of large amounts of biologic data (sequences, various -omics) and ultimately for rational design of therapies for disease processes. Metabolic networks are highly organised to execute their function efficiently while tolerating wide variation in their environment. These networks are constrained by physical requirements (e.g. conservation of energy, redox and small moieties) but are also remarkably robust and evolvable. The authors use well-known features of the stoichiometry of bacterial metabolic networks to demonstrate how network architecture facilitates such capabilities, and to develop a minimal abstract metabolism which incorporates the known features of the stoichiometry and respects the constraints on enzymes and reactions. This model shows that the essential functionality and constraints drive the tradeoffs between robustness and fragility, as well as the large-scale structure and organisation of the whole network, particularly high variability. The authors emphasise how domain-specific constraints and tradeoffs imposed by the environment are important factors in shaping stoichiometry. Importantly, the consequence of these highly organised tradeoffs and tolerances is an architecture that has a highly structured modularity that is self-dissimilar and scale-rich.

Animals↗

Proline residue-modified polycationic analogs of gramicidin S with high antibacterial activity against both Gram-positive and Gram-negative bacteria and low hemolytic activity.

Novel polycationic analogs of the cyclic decapeptide antibiotic, gramicidin S, possessing NH(2), D/L-Phe-NH or L-Lys-NH groups at the 4alpha- or 4beta-positions of the L-Pro residues, were synthesized. While L-Pro(4alpha/beta-NH(2))-containing analogs exhibited much weaker antibacterial activity, the D/L-Phe and L-Lys-substituted analogs exhibited higher antibacterial activity against Gram-negative bacteria than the parent gramicidin S. All of these additional amino group-containing analogs showed substantially reduced toxicity against human blood cells.

Amination↗

Histone deacetylase inhibitors, N-butyric acid and trichostatin A, induce caspase-8- but not caspase-9-dependent apoptosis in human malignant glioma cells.

Histone deacetylase (HDAC) inhibitors have both apoptotic and differentiating effects on various tumor cells. However, the mechanisms underlying the effect of HDAC inhibitors remain unclear. In this study, we investigated the function of anti-proliferative effects of HDAC inhibitors, N-butyric acid and trichostatin A, on human malignant glioma cell lines, U251-MG and D54. MTT assay showed a dose-dependent inhibition of cellular proliferation in both cell lines. Cell cycle analysis revealed increased sub-G1 population in both lines, and G1 arrest only in U251-MG cells. Induction of apoptosis was also supported by the occurrence of DNA fragmentation in tumor cells treated with HDAC inhibitors. Furthermore, caspase inhibition assay indicated that HDAC inhibitor-induced apoptosis was caspase-dependent. Neither mitochondrial membrane potential nor the expression of caspase-9 was changed by treatment with HDAC inhibitors, suggesting the possibility that HDAC inhibitor-induced apoptosis was not mediated by the mitochondrial cell death pathway. On the other hand, immunoblot assay confirmed increased expression of caspase-8 in both lines, and elevation of p21 but not p27 protein in U251-MG cells following HDAC inhibitor treatment. Taken together, the HDAC inhibitors, N-butyric acid and trichostatin A, induce caspase-8- but not caspase-9-dependent apoptosis with or without p21-mediated G1 arrest in human malignant glioma cells.

Apoptosis↗

Effectiveness of flow stabilization in small-scale wastewater treatment facilities.

Household type Johkasous which have a flow stabilization function were surveyed on their performance. The water level, flow velocity and SS were measured after the maximum flow entering the anaerobic filter chamber with or without flow stabilization operation. In operation without the flow stabilization, the flow peak directly reached the biofiltration chamber and the flow rate kept at 1 cm/sec during 3-4 min in the connection baffle between the two anaerobic chambers. This suggested the possibility of sludge transfer from the first anaerobic chamber. Moreover the increase of SS in the second anaerobic chamber indicated sludge transfer from the second anaerobic chamber to the biofiltration chamber. In contrast, in operation with flow stabilization the relaxation of the water flow in the second anaerobic chamber and the biofilm chamber was verified. By the increase of the water level in the first anaerobic chamber, the flow stabilization performance was satisfactorily obtained. A model describing the change of the water level was developed and the calculated values and the measured value agreed well. The model will be useful in the design of the flow stabilization function.

Evaluation Studies as Topic↗

Domain structures of chlorophyllide a oxygenase of green plants and Prochlorothrix hollandica in relation to catalytic functions.

Chlorophyll b is a photosynthetic antenna pigment found in prochlorophytes and chlorophytes. In chlorophytes, its biosynthesis regulates the photosynthetic antenna size. Chlorophyll b is synthesized from chlorophyll a in a two-step oxygenation reaction by chlorophyllide a oxygenase (CAO). In this study, we first identified the entire sequence of a prochlorophyte CAO gene from Prochlorothrix hollandica to compare it with those from chlorophytes, and we examined the catalytic activity of the gene product. Southern blot analysis showed that the CAO gene is presented in one copy in the P. hollandica genome. The P. hollandica CAO gene (PhCAO) has a coding capacity for 367 amino acids, which is much smaller than that of Arabidopsis thaliana (537 amino acids) and Oryza sativa (542 amino acids) CAO genes. In spite of the small size, PhCAO catalyzed the formation of chlorophyll b. By comparing these sequences, we classified the land-plant sequences into four parts: the N-terminal sequence predicted to be a transit peptide, the successive conserved sequence unique in land plants (A-domain, 134 amino acids), a less-conserved sequence (B-domain, 30 amino acids) and the C-terminal conserved sequence common in chlorophytes and prochlorophytes (C-domain, 337 to 344 amino acids). We demonstrated that the C-domain is sufficient for catalytic activity by transforming the cyanobacterium Synechocystis sp. PCC6803 with the C-domain from A. thaliana. In this paper, the role of the A-domain is discussed in relation to the formation of light-harvesting chlorophyll a/b-protein complexes in land plants.

Amino Acid Sequence↗

The evaluation of autonomic nervous function in a patient with hereditary sensory and autonomic neuropathy type IV with novel mutations of the TRKA gene.

We report on a 10-year-old girl with anhidrosis and insensibility to pain, but no severe mental retardation or self-mutilation, diagnosed as hereditary sensory and autonomic neuropathy type IV (HSAN IV). Genetic analysis of her TRKA gene, which is responsible for HSAN IV, revealed two novel missense mutations in the tyrosine kinase domain. Cardiovascular autonomic nervous system function tests showed normal muscle sympathetic nerve activity associated with arterial baroreflex, reduced skin sympathetic nerve activity in the second and fifth fingers and palms, and abnormal circadian rhythm of cardiovascular autonomic nervous system. These findings have never before been reported in HSAN IV and may provide a clue to the neurological pathophysiology of this disease.

Autonomic Nervous System↗

Therapeutic efficacy of targeting chemotherapy using local hyperthermia and thermosensitive liposome: evaluation of drug distribution in a rat glioma model.

A method was developed of targeting chemotherapy using thermosensitive liposomes to treat malignant gliomas. Using the brain heating system, when the tumour core is heated to >43 degrees C, the tumour infiltrating zone is exposed to mild hyperthermia (40-43 degrees C). Thermosensitive liposomes were designed to release their contents at 40 degrees C to target both the tumour core and tumour infiltrating zone. The present study investigated the anti-tumour effect on rat glioma models in tumour drug uptake and tumour growth delay studies. Elevated accumulation of ADR in the rat C6 glioma after treatment was obtained in the area heated to >40 degrees C. However, there was no significant difference between the areas heated to 40-42 degrees C and >43 degrees C. Furthermore, it was found that ADR concentrations in the mildly hyperthermic areas were significantly higher following treatment with liposomal ADR than with free ADR. The animals treated with the new combination therapy had significantly longer overall survival time in comparison to those receiving other treatments. Thus, thermosensitive liposomes release their contents in response to mild hyperthermia and this combination therapy has a greater therapeutic efficacy for malignant brain tumours. This method is a promising approach for the treatment of malignant glioma patients.

Animals↗